CERTAIN IMPROVED MODES OF CONSTRUCTING THE LOCKS AND SLUICES OF CANALS, BASONS, Docks, AND GENERALLY FOR THE TRANSPORTATION OF FLOATING BODIES PROM ONE LEVEL TO ANOTHER
Year: 1813

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, J, COLONEL
WILLIAM CONGREVE, of Cecil Street, in the City of Westminster, and County
of Middlesex, send greeting.
WHEREAS His most Excellent. Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-third day of
March, in the fifty-third year of His reign, give and grant unto me, the said
William Congreve, my exors, admors, and assigns, His especial licence, full
power; sole privilege and authority, that I, the said William Congreve, my
exors, adors, and assigns, should and lawfully might, during the term.of
years therein mentioned, make, use, exercise, and vend, within England',
Wales, and the Town of Berwick-upon-Tweed, my Invention of "CERTAIN
IMPROVED MODES OF CONSTRUCTING THE LOCKS AND SLUICES OF CANALS, BASONS,
Docks, AND GENERALLY FOR THE TRANSPORTATION OF FLOATING BODIES PROM ONE
LEVEL TO ANOTHER;" in which said Letters Patent there is contained a proviso
that if I, the said William Congreve, shall not particularly describe and
ascertain the nature of my said Invention, and in what manner the same is
to be performed, by an instrument in writing under my hand and seal, and
cause the same to be inrolled in His Majesty's High Court of Chancery
within two calendar months next and immediately after the date of the said
Letters Patent, that then the said Letters Patent, and all liberties and
advantages whatsoever thereby granted, shall utterly cease, determine, and
become void, 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
William Congreve, do hereby declare that the nature of my said Invention,

page_text: and the manner in which the same is to be performed, are particularly described
and ascertained in and by the Drawing hereunto annexed, and the following
description (that is say):-
My first mode of passing floating bodies from one level to another, by what
I call the hydro-pneumatic double-balance lock, is thus constructed :-
Fig. 1. A, B, C, D (Fig. 1), is a transverse section of the masonry of two
locks, formed by the two side walls A, C, and the middle wall B dividing the
whole into two equal parts (these being of sufficient strength), and of D, D, the
foundation. Within the walls A & B, B & C, that is to say, round the inside
of each lock, a minor wall G, G, & H, H, is constructed at a small distance
from the main walls, the height of these minor walls being always from six
inches to one foot more than the difference of level. A channel of communica-
tion E, F, is also provided between the two locks, either formed by arches
through the masonry itself, or in the foundation, or by iron or other tubes
below it. This completes the fixed or stationary parts of the construction.
We now come to the moveable or detached parts, and these consist of two
inverted caissons a, a, b, b, miade either of wood or iron or other metal, or a
combination of both, the area of each being so nearly equal to that of the
area of each lock that they may be just raised up and down in the locks
without touching the sides, and the sides of these caissons a, e, a, e, & b, d,
being so adjusted that they may work up and down between the main
walls A, B, & B, C, and the minor walls G, G, & H, H, in each lock also
without touching, and yet leaving the least possible interval, the depth of
these sides being always equal to the height of the minor walls. There
remains only to state that these caissons are connected by a chain O, P,
passing over rollers X, Y, so that the raising of one must depress the other,
and of such a length as to allow the quantity of action required for the
intended difference of level to be passed in the lock, and this compleats all the
essential parts of the apparatus. We have now therefore to put this
apparatus into a state of action. Let one of these caissons, as in the
Diagram Fig. 1, be raised for the upper level, the other be down for the lower
level; in this situation an equal quantity of water is to be poured from the
upper level into each of the locks at the same instant until a sufficient quan-
tity be accumulated on the upper caisson, so as to be on a level with the
water on the upper level of the canal; the locks will then be found to be
charged and ready for action; the caissons will both support themselves, and
will shift alternately up and down in the application either of a depressing
power to the highest, or a lifting power to the lowest, provided the water has
in this operation flowed in equal quantities upon both caissons, if not, the

page_text: adjustment will be compleated on the first shift by opening the gate of the
upper level into the lock then raised, after which (defects of workmanship
excluded) it will work two barges at a time, whatever their difference of
weights may be, without the loss of any water whatever. Now the principle
of action is as follows:-By pouring water on both caissons at the same time
a quantity of air is confined between the water W, W, in each lock, which
air, although it may circulate freely from under one caisson to the other
through the channel of communication F, F, cannot escape by the
spaces left
between the main walls and the caissons owing to the minor walls being
always so arranged, with respect to the caisson, as to overlap about a foot, by
which means the air, being always kept above the water that compresses it, is
completely conâined, and being so confined it becomes compressed to a certain
degree proportionate to the height of the required column by the flowing of a
certain quantity wiv over the top of the minor walls until its compression
balances the acting column of water in the lock, which is always equal to the
water above the caisson, plus the depth of the caisson, minus the over-lapping.
By this arrangement, therefore, it is evident that we have two equal quantities
of water in a mean state of equipoise with each other, the air beneath them
acting the part both of the beam, and the sides of the scale moving without
other friction than that of the water and air, the former against the sides of
the lock, and the latter through the channel of communication; for all the
friction that would at first sight be expected from the chain passing over the
rollers may be done away by loading the caisson with weight exactly equal to
the buoyant pressure of the air under it, and this may be done either by solid
weight or by making the caisson of the form expressed by the dotted
lines m, n. p, q, and filling this space with water, which, with the weight of the
caisson itself, may be so adjusted as to make the whole weight precisely equal.
to the buoyancy of the air, so as to leave no strain on the chain or friction to
overcome. It is true there is less water on the top of the caisson when
elevated than when down; these quantities are equal when the caissions
are on the same level, and the balance is then perfect; but an accumulation
from this point downwards takes place, and a power is gained, which being
applied on each side to raise an adjusting or compensating weight, makes the
balance in fact perfect in every part of the lift,. and leaves therefore, in com-
puting the power necessary to change the level (for the weight on each lock
remains the same whether there be a barge in it or not), that effort only to be
estimated which is sufficient to overcome inertia, and the actual weight of the
quantity of air transferred from one side to the other at the rate of one ounce
per cubic foot, a quantity which, though not hitherto mentioned, must not be

page_text: neglected, as it is in fact: the only thing that prevents this system being
reduced to an absolute equipoise; it is but a small quantity after all.
Having said thus much therefore in description of this construction, the
mode of charging it, its principle of action, and of the. power required to
effect the changes,. I shall. proceed to the different modes of applying this
power. On the principle of saving all the lockage water, this power must be
obtained by some external agency, and I conceive the effort of one or two men
in about one minute would change. the level of an ordinary lock, either by the
common wheel and axle, or by the rack and pinion; &c.; or one man may be
employed at his leisure in. raising a number of weights, each equal to the
effort required for each shift, to overcome the inertia, &c. above stated, which
weight may be thrown into action for that shift when required, and so in its
turn wound up again at leisure. In this way I am convinced that one man
would in the course of the day accumulate at his leisure a sufficient quantity
of power. to do the common work. of the lock; but this lock may at any
time also be worked by a sacrifice of a certain quantity of lockage water
in the simplest mode, and by a. process requiring no time to perform it,
without the variation of a single. particle of its construction, merely,
in making the lift, by taking. care to raise the upper level in the lock
only to a certain distance u short of U, the upper level in the canal;
this will also bring the lower level in the lock. to a little short of L, the
lower level in the canal. The sluice being then opened, an accumulation
of weight in an instant takes place in the upper caisson, and a diminution
on the lower, which will immediately shift. the levels on the handle of the
wheel and axle, a rack and pinion being freed, that being sufficient to serve as
a stop and regulator of this spontaneous action, as well as a mover, when the
shift is performed by external agency. There remains only one circumstance
more to notice respecting this principle of lock, namely, the mode of regu-
lating it when any variation takes place in either. level of the canal above or
below their standart heights. The adjustment may be made in a very simple
mode, involving no sacrifice of water, and producing only this difference in the
working, that whereas when both the levels are at the standard height, the
alternate upper and lower gates may be opened at the same instant, so that
both barges may pass in at once. Whilst in the different cases of this
variation in the standard level the gates must be opened and shut separately,
the level in each lock requiring to be brought separately to the level of its
respective part of the canal. In this mode of regulation there is one, and
only one, situation in which there is a reverse action on the lower gates,
namely, when the upper level is above its standard and the lower one not so;

page_text: the pressure, however, in this case cannot be supposed at any time to exceed
a.column of one foot, and may be guarded against either by a moveable sill;
as it may be termed, at the bottom of the lower gates, to secure them when
this necessity occurs; or this inverted pressure may be got rid of, and indeed
the adjustments made in all the cases, by regulating the levels in the locks
by a small flow of water to or from the deviating. level of the canal, on the
same principle as when these locks are worked by water, as above explained.
It is. here to be observed, that it is not necessary that the caissons should be
formed in one entire vessel; they may be subdivided into any number of
separte parts or vessels that may be deemed necessary to insure sufficient
strength, according to the magnitude of the locks, the inner walls G, G,
H, H, being divided also into similar compartments, by which arrangement
any accident happening to any of the subdivided caissons the faulty part may
be removed without disturbing the whole.
I shall now procced to specify certain varieties that may be made on this
principle of lock, not that I consider them to be improvements, but merely as
matters of caution to guard against any violation of this Patent that might
arise from the production of any such variety hereafter. In the first place, the
lock has hitherto been considered merely a double one, the principal and
co-agent being alternate, and both mutually serving the double purpose of
lock and counterpoise in the balancing system. This, however, although the
best construction, because, independent of the double action, it affords the
means of working the canal at all times, even when the locks may be under
repair, is not indispensible. The lock may be made a single one, and the
co-agent may be a detached part, acting only as a counterpoise, in which case
the form may be varied in any way. This detached part or co-agent also
need not be constructed on the same principle as the lock itself, but may be
formed of a certain number of cylinders. with solid loaded pistons, or it may
consist of a close cylinder or other vessel, wherein the raising or falling of the
caisson and the water in the lock may be effected by the expansion and con-
densation or accession and escape of any gas, air, or steam, so also this prin-
ciple may be put into action either on the double or single construction, by
filling the space under the caissons with any fluid lighter than water in lieu
of the air;; and again it may be effected, without requiring that. the air under
the caissons should be in a state of compression, by filling the space between
the main and minor walls in which the sides of the caisson work with. any.
fluid heavier than water, as with quicksilver. With respect to the hydro-
pneumatic lock, I shall only add, that other matters may be substituted for the
minor walls of masonry, G, G, H, H.

page_text: I shall now proceed to specify certain modes of another system of double-
balance locks, founded also on the principle of establishing and regulating an
equilibrium between weight and buoyancy, by which I propose to effect the
transporting of floating bodies from one level to another, under circumstances
similar to those already described as to the saving of labour and lockage
water, but with a variety as to arrangement. This system may be termed the
Lalloon double-balance locks, and is constructed as follows:-
Fig. 2. A, B, C, Fig. 2d, represents a transverse section of the three main
walls of a double lock, fitted with the ordinary upper and lower canal gates, consti-
tuted nearly as in Fig. 1, but with this difference, that an archway E, F, or arch-
ways, are formed in the middle wall B; two inverted caissons a, a, b, b, which
I denominate the balloons, nearly fitting each lock, are then placed therein,
having a compleat interior lock m, n, p, q, fixed upon them, of the same area
as themselves, and having a compleat set of gates, &c. so adjusted as to fit
close to those of the outer lock; this interior lock being sufficient to receive
and float the barge in or out on the opening of the double gates; the outer
locks or wells are then half filled with water, and the two caissons or balloons
being connected by a chain O, P, and double fuzee, so that when one is up
the other must be down. It is evident that there is here also a system of
equipoise established, by which two barges may be passed at the same time,
for the whole effort of the immersed or lower caisson to rise will be precisely
equal to the whole resistance of the floating or upper caisson to sink. Though
these two quantities vary with respect to each other in different positions of the
ascent and descent, these variations of effect however being equalized by
the double spiral wheel, and the water in the outer lock or well always
remaining at the same height, by the communication E, F, the balance
becomes uniform in all points, and the application of power to produce the
change of levels may be made under similar circumstances to that above
specified, and may either be effected by the wheel and axle, rack and
pinion, &c., or by the sacrifice of a small quantity of water into the lower
level from the lower inner lock W, and an addition from the upper level to
the upper inner lock W, by shifting the two surfaces of W, W, to u and I short
of the full distance of the upper and lower levels U, L, of the canal, as specified
with regard to one of the modes of working the hydro-pneumatic lock. This
system may be applied either for a small or great lift, and may have the
interior lock fixed directly down upon the buoyant caisson, or balloon as it is
here designated, in which case a part of the caisson occasionally emerges from
the water of the outer lock; or the interior lock may be fixed to the caisson
at any height above it, in which case the caisson need never emerge from the

page_text: water, and this dispenses with a part of the compensating weights. The
caissons or balloons may also be made with or without a bottom, hollow and
air-tight, or of any solid & light substance. On this principle also the lock
may be constructed, either double or single, retaining the property of being
balanced so as to work with facility either by the wheel and axle, rack and
pinion, or by a moderate sacrifice of water, as above specified. It must
here, however, be observed, that no possible variety of locks can be con-
structed on this principle without having the double setts of gates and sluices
(that is to say), a compleat sett for the inner lock and another compleat sett
for the outer one, or something to answer the same purpose.
There remains a third system of double-balance locks, founded also on the
principle of establishing and regulating an equilibrium between weight and
buoyancy, of which I shall specify certain constructions. This system may be
called the buoyant plunger lock.
Fig. 3. A, B, C, Fig. 3d, represents a transverse section of the three main
walls of a double lock, in which, however, there is no communication whatever
between the locks A, B, B, C. These locks being each of them double the
breadth of the barge intended to be passed, half of the space is filled by an air-
tight or buoyant plunger a, a, & b, b, with or without a bottom, or they may, as
above, be formed of a light solid substance. Now, each of these locks being
half filled with water, and the caissons being so connected by the chain
O, P, and double fuzee S, that when a, a, rises b, b, will be depressed, and
vice versa, and being also equal, they displace equal quantities of water; their
buoyances therefore are equal and in contrary directions, tho' varying as above
in quantity at different points of ascent and descent, this variation being,
however, as before, equalized by the double spiral wheel S. Similar powers
to those above explained (that is to say), the wheel and axle, rack and pinion,
&c., and also the mode by adding to the water in the upper lock and taking
from that in the lower one, will be found to produce the alternate positions of
up and down in the caissons in the system as well as in the foregoing, and
consequently will raise the water on the side where the caisson is immersed,
and lower it on that side where the caisson is raised, so as alternately to
change the levels of the water in the locks. This mode of changing the
level may also be applied in a single lock by a counterpoise, as stated of the
last system.
It remains only to be observed, that in all the possible varieties
of this system a caisson equal in cubical content to the whole water contained
in the lock is necessary, but that in no case is required more than the single
sett of gates, the water being in this, as in the hydro-pneumatic lock, raised
in immediate contact with the gates of the canal itself.

page_text: I shall conclude this Specification by stating, that all that is herein con-
tained applies generally to any difference of level, whether in canals, rivers,
docks, or whatever else it may be; and further, that any one of these
systems is applicable to the passing burthens over any difference of level in
railways, also by side ponds or reservoirs, which need not be of any very con-
siderable size, and will not require any frequent supply of water where the
burthens passing up and down in given times are nearly equal, as that cir-
cumstance will constantly regulate and restore the quantities of the said
reservoirs so as to work the floating platform on which the waggons, carts, &c.
are to pass up and down; and in fact the same application made be made for
the purpose of loading and unloading warehouses, where the up and down
work is necessarily equal in certain times, upon large moveable and floating
platforms, balanced by reservoirs at top and bottom. I shall only add, that
for this purpose the single balloon principle above stated is perhaps the best
adapted, where, by having a deep well containing à caisson of sufficient
buoyancy with a water vessel and floating platform supported upon it by an
upright beam of any length, proportioned to the depth of the well, any
quantity of goods may be raised to any height of warehouse with the least
possible labour. I do not propose this as being so desirable in its application
for the lifting of single packages, but for the raising and lowering large
quantities of goods in one lift, by which a very great. proportion of time would
be saved in this description of work.
In witness whereof, I, the said William Congreve, have hereunto set my
hand and seal, this Twenty-second day of May, in the year of our