IMPROVED METHOD AND MACHINE FOR PASSING BOATES, BARGES, AND OTHER VESSELS FROM A HIGHER TO A LOWER LEVEL, AND THE CONTRARY," WITHOUT LOSS OF WATER
Year: 1815

page_text: BAGOT'S SPECIFICATION.
TO. ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BAGOT, of Birmingham, in the County of Warwick, Surveyor, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fourth day of April, in the fifty-fifth year of His reign, did give
and grant His especial licence unto me, the said Thomas Bagot, my exors,
admors, and assigns, during the term of years therein expressed, to make, use,
exercise, and vend, within England, Wales, and Town of Berwick-upon-
Tweed, my "IMPROVED METHOD AND MACHINE FOR PASSING BOATES, BARGES,
AND OTHER VESSELS FROM A HIGHER TO A LOWER LEVEL, AND THE CONTRARY,"
WITHOUT LOSS OF WATER;" in which Letters Patent there is contained a
proviso obliging me, the said Thomas Bagot, under my hand and seal, to
cause a particular description of the nature of my said Invention, and in what
manner the same is to be performed, to be inrolled in His Majesty's High
Court of Chancery within three calendar months next and immediately after
the date of the said recited Letters Patent, as in and by the same, relation
being thereunto had, may appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Bagot, do hereby declare the nature of my said Invention, and the
manner in which the same is to be performed, is described in the Drawings
and Specification in these Presents contained (that is to say):→
Let U in the plan represent the upper level of a canal, and L the
lower level thereof; and let A, A, A, A, in the plan and section represent
the walls of a lock or locks, connecting in the usual manner by means

page_text: of sluice gates u, u, and l, l, in the plan; U the upper, and L the
lower levels of the said canal; and let B, B, B, in the plan and section
represent the walls of a reservoir which I denominate the forcing chamber.
The walls of such lock or locks and reservoir being supposed to be built in a
firm and durable manner of brick, stone, or other proper materials or com-
bination of materials capable of containing water without leakage, and of a
sufficient strength to resist the utmost hydrostatic pressure that may at any
time be exerted upon. them; and let the reservoir, which I call the forcing
chamber, communicate at the bottom or the lower part thereof with the lower
level of the said canal by a conduit or conduits marked C in the plan, fur-
nished with a valve or set of valves V, V, V, in the plan, opening inwards
into the said forcing chamber,. and, let their be a conduit or conduits, as
shewn at ba, ba, in the plan and section, forming a communication
between the lower part of the said forcing chamber and the lock or locks;
such conduit or conduits being furnished with a valve or valves, as shewn at a
in the section, opening inwards into the said lock or locks, and with a paddle
or paddles at b, b, next the said reservoir or forcing chamber, to cut off the
communication between the forcing chamber and either lock, as may be
required. Let p, p, p, p, denote paddles in 1, 2, the lower gates of each
lock, as shewn in the plan, which paddles, being drawn, open a commu-
nication between each lock and the lower level of the said canal, and, by
drawing such paddle or paddles, the lock or locks are emptied of water.
W denotes a weir to carry off any surplus or waste water by c, c, c, c, c, a
culver or culvers from U, the upper level of the said canal, to L, the lower
level thereof, and to equalize the depth of water in the different ponds or levels
of the said canal. ff.ff. denote foot bridges firmly fixed and attached to
the upper and lower gates of the locks, which bridges form a communication
between the locks and the towing paths; or opposite sides of the said canal,
as may be required. And let the dotted quadrantal arcs and arrows shew the
direction in which u, u, the upper, and 1, 1, the lower gates of the said locks
open. In addition to the above, let there be a vessel constructed and made
buoyant, which I denominate an evacator, of such dimensions as just to float
in the said forcing chamber without touching the sides thereof, which evacator
may be formed of iron, wood, or any other proper material or combination of
materials, capable of being made water-tight; and let such evacator be for
nished with a valve or valves to regulate the weight with which it may be
loaded, by suffering a quantity of water, if necessary, to flow into it, equal to
the degree of buoyancy which it may be required to possess; and let such
evacator be furnished with a manhole or holes similar to the boiler of a steam

page_text: engine, to enable the internal part to be at any time inspected, if found neces-
sary. Now, there is a regular communication between the lower level of the
canal and the lock or locks between such lower level of the canal and the
forcing chamber, and likewise between the forcing chamber and lock or locks
through the respective conduits, as shewn by the direction of the arrows,
except when such communication shall be cut off either by the paddles
between the forcing chamber and locks being let down, or by the action of the
valves, as hereafter mentioned. It follows that the water in the lower level
of the canal, in the forcing chamber and locks, will each have one common
level, and from which level I intend to derive the water I may require to pass
any boat, barge, or other vessel, as by the following examples will clearly
appear. Suppose it were required to pass two boats, barges, or other vessels
from the lower pond or level L of the canal into the upper one U at one
time, I suppose the boates, barges, or other vessels are floated into the respec-
tive locks designated by the italic letters A and B, the lower gates 1, l, shut,
and the paddles p, p, p, p, in each of the lower gates let down or closed; the
communication is now cut off between each lock and the lower level of the
canal, except through the conduits C and b→ a, b → a. Now, supposing a
pressure to be exerted on the upper surface of the evacator which floats in the
forcing chamber sufficient to overcome the buoyancy thereof, the evacator will
sink in the forcing chamber and thereby displace a bulk of water equal to
the cubical content of the part immersed by such pressure.. Immediately
on such pressure being applied to the valve or valves v, u, v, (connecting,
by means of the conduit or conduits C, the forcing chamber with the lower
level of the canal), close, and those shewn at a, a, opening inwards into
each lock open, and the water in the forcing chamber, by such depression and
force, is driven out of the reservoir or floating chamber into each lock
(although I here use the term driven, the water really falls, in consequence
of its hydrostatic head or pressure, for, as the pressure is exerted on the
evacator it displaces a column of water equal to the cubical content of the
part immersed, as before stated; and being so displaced, a portion of the water
rises up by the sides of the evacator so immersed and acts, by the following
law of hydrostatics, that a column of water, however small in its lateral dimen-
sions, will balance or equipoise a column of water however large, if there be
a communication formed between them). The water in the forcing chamber,
being by the downward pressure of the evacator forced into each lock, is now
considerably below the line of level of the lower pond of the canal, and the
pressure upon the evacator in the forcing chamber being removed, the water
immediately, by its hydrostatic pressure, opens the valves u, v, v, and rushes

page_text: through the conduit C, in the direction of the arrows, into the forcing
chamber to restore it to the level of the lower pond of canal. The pressure
being again exerted upon the evactor, the water is again driven into the locks
by the valves v, v, v, closing, and those of a, a, opening by the pressure of the
column of water upon them. And the forcing chamber being or supposed here
of equal surface or area with each lock, and the lock having seven feet rise,
if the evacator be made to sink in the forcing chamber at each depression
two feet and four inches, or a little more, both locks will then be filled
by six depressions of the evacator, and the upper gates of the locks being
now opened, the boats, barges, or other vessels float out of each lock into the
upper pond or level of the canal. Now, the water in each lock A and B
being raised to the upper level U of the canal, supposing there was only one
boat, barge, or other vessel ready to descend to the lower level of the canal,
which boat, barge, or other vessel (no matter whether empty or loaded) I will
suppose floated into the lock A, and the upper gate u being closed, the paddles
p. p, in the lower gate of the lock being drawn, the communication is now
opened between the water in the lock and the lower level of the canal, the
water in the lock A subsides, and the boat, barge, or other vessel upon the
lower gate of the lock being opened floats into the lower level L of the canal.
We now find the lock A empty (as it is called), or upon the same level with
the lower pond of canal, and the lock B full or upon the same level with the
upper pond of canal. Now, let us suppose a boat, barge, or other vessel in
the lower pond of the canal is required to be raised to the upper level thereof,
and that a boat, barge, or other vessel in the upper pond of canal is wanted to
be passed to the lower level thereof at the same time, in the first place, let fall
the paddles at b, b, at the end of the conduits connecting the lock B with the
forcing chamber. The communication between the forcing chamber and the
loak B being now cut off, draw the paddles p, p, in the lower lock gates of
the lock B, and the boat, barge, or other vessel in that lock will be depressed
to the lower level of the canal; then apply the depressing force to the
evacator, and the water that is in the forcing chamber will immediately rush
through the conduits ba, ba into the lock A, and raise the water
and the boat, barge, or other vessel therein. And the evacator at each de-
pression thereof sinking two feet and four inches or a little more, at three such
depressions, the boat, barge, or other vessel is raised to the upper level of the
canal and floats thereout on the upper gate u of the lock A, being opened, at
the same time that the boat, barge, or other vessel in the lock B being
depressed to the lower level of the canal floats into the lower pond of the
canal on the lower.gate I of the lock B being opened. And by this means

page_text: an alternate trade to any practicable extent may be carried on without the loss
of any water whatever, reducing the supply necessary for inland navigation
merely to the evaporation from the surface, and the leakage attendant upon
canals in general.
And I hereby declare, that for the purpose of giving a motive force to,
and effecting the depression of, the evacator in the forcing chamber, I
employ the power of the hydrostatic press, for which the late Mr. Bramah
obtained a Patent; but instead of using the said press in the manner
described in his Specification, I alter and reverse the action thereof by
inverting the large cylinder of the press and making the piston thereof to
act downwards, or in the direction of gravity, instead of acting upwards,
as therein described. And for effecting this purpose I cause a strong
framing of iron or other metal, or any other durable substance, of sufficient
strength to resist the utmost stress that the press may be required at any time to
exert on the evacator, to be firmly fixed in the walls of such forcing chamber;
to the transverse part of which framing I affix in a firm and durable manner,
and in an inverted position, the large cylinder of the bydrostatic press, in which
the piston which depresses the evacator slides, and which cylinder having a
communication with a small forcing pump or pumps, by injecting water or
other fluids into the large cylinder, gives motion to the piston thereof, and
thereby effects the depression of the evacator in the forcing chamber; and the
pressure of the forcing pump being removed by opening the discharging valve,
or in any other way, the water in the lower pond of the canal raises the
evacator, and with it the piston of the large cylinder to its former situation and
level, and the operation may be again repeated as herein-before described.
And for the purpose of giving quickness to the operations thereof, I apply
thereto in some cases two or more small forcing pumps, worked by one or
more levers, as may be thought necessary, which additional pump or pumps
will give such celerity to the motion of the evacator in the forcing chamber.
that the water in the lock may be raised with much more speed than it is at
present done in the best constructed locks, which hydrostatic press as altered
and applied by me to the purposes herein stated and set forth, I denominate
and call the depressor.
In the present construction of locks there are conduits built in the
walls thereof, connecting the upper level of the canal with the inside of
the lock, and in many instances conduits are built connecting the inside
of the lock with the lower level of the 'canal, with paddles adapted
thereto to cut off the communications between the ponds of the canal and
lock as may be required. The improvements which I propose to make

page_text: thereon is, to simplify the lock by constructing the walls thereof of solid
masonry, except in those places where communications are to be made with
the forcing chamber as before specified, thereby increasing the strength and
durability of the lock and lessening the expense of erecting them and keeping
them afterwards in repair.
Another improvement I propose is, to hang the lock gates on the opposite
or off side of the lock, as shewn in the plan, and directly contrary to the
position they are at present placed in, by which means the towing paths are
kept open, and free from obstructions, greater facility is given to the passing
of horses, &c. in hauling the boats, barges, or other vessels, the levers or
arms of the lock gates may be made of greater length so as to act as a more
perfect equipoise thereto, and, being out of the way of the haulers and towing
ropes, become less liable to injury from the friction thereof, and will be more
durable. And I do further declare, that I adapt such part of my foregoing
improvements as regards the saving of water to locks on the present construc-
tion by causing a perforation or opening to be made in the wall or other part
of such locks, and thereby forming a communication or communications with
a forcing chamber to be added thereto, which forcing chamber must in all
cases have a communication, as before described, with the lower level of the
canal; and in case of its being a single lock, adapting the valves only to the
inside of the forcing chamber and of the lock, for reasons which are hereafter
mentioned, so that the lock may then be used either with or without the
improvement at any time as may be thought necessary. And although in the
Drawings and Specification herein contained I have given the principles
and plan of operation as applied to two locks, or what is generally termed
a double lock, yet the same principle and mode of operation may be
equally applied to a single lock, tho' in this case the paddles as described
and shewn at the extremity 6, 6, of the conduits 6 a, b, a, in the
plan and section will not be necessary, they being only useful when the
principles developed in this' Specification are applied to the compound opera-
tion of two locks, or what is generally termed a double lock. And I hereby
declare, that the principles and machine here set forth and described may be
adapted to canals and sluices of all descriptions, and varied in all degrees of
magnitude, so as to pass or raise vessels from a lower to a higher level and
the contrary, with the greatest possible celerity, from one to one thousand tons
burthen and upwards. And although in the Drawings accompanying this
Specification I have described the forcing chamber as having an equal area
with each lock, and as being rectangular, yet the form and dimensions thereof
may be varied at pleasure. And although I have not mentioned of what

page_text: materials the conduits are to be constructed, yet I consider they may be
formed of masonry, or may be made of cast iron, with valves fitted to the ends
thereof, or in any other way that may be deemed most effectual for the
purposes s intended. And although I have described the operations of effecting
the elevation of the boat, barge, or other vessel in the lock by the depression
of the evacator, yet it will be immediately seen that the same may be per-
formed by loading the evacator with water, so as to have a preponderance
therein and balancing the weight thereof by an equipoise or counter-weight,
and giving motion thereto by racks, pullies, wheels, and pinions, or other well-
known mechanical contrivances, or effecting the same by making the power
of the hydrostatic press act upwards upon the evacator. But tho' I men-
tioned these different modes of construction to prevent any evasion of the
principles of my said Invention, or any part thereof, yet I consider the mode
I have laid down in this my Specification as the best adapted to effect the
purposes wanting in the most effectual, cheap, and expeditious manner.
In witness whereof, I have hereunto set my hand and seal, this Twenty-