A NEW MODE OF EXCLUDING THE WATER OF THE SEA, OF RIVERS, OR OF LAKES, TEMPORALLY, DURING THE EXECUTION OF UNDER-WATER WORKS OF MASONRY OR OTHER MATERIALS, OR. PERMANENTLY FOR THE SECURITY OF FOUNDATIONS, APPLICABLE, FOR EXAMPLE, TO THE CONSTRUCTION OF SEA WALLS, WHARFS, PIERS, DOCKS, AND BRIDGES
Year: 1812

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I. SAMUEL
BENTHAM, of Hampstead. in the County of Middlesex. Civil Architect, and
Engineer of His Majesty's Navy, 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 Fifth day of March,
in the fifty-second year of His reign, give and grant unto me, the said
Samuel Bentham, my exors, admors, and assigns, His especial licence, full
power, sole privilege and authority, that I, the said Samuel Bentham, my
exors, admors, 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 "A NEW
MODE OF EXCLUDING THE WATER OF THE SEA, OF RIVERS, OR OF LAKES, TEMPORALLY,
DURING THE EXECUTION OF UNDER-WATER WORKS OF MASONRY OR OTHER MATERIALS,
OR. PERMANENTLY FOR THE SECURITY OF FOUNDATIONS, APPLICABLE, FOR EXAMPLE,
TO THE CONSTRUCTION OF SEA WALLS, WHARFS, PIERS, DOCKS, AND BRIDGES;" in
which said Letiers Patent there is contained a proviso that if I. the said
Samuel Bentham, shall not particularly describe and ascertain the nature of
my said Invention. and the manner in which the same is to be performed.
by an instrument in writing under my hand and seal, and cause the same to
be enrolled 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 these Our Letters Patent, and all liberties and advantages whatsoever
thereby granted, shall utterly cease, determine, and become void, as in and

page_text: appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Samuel Bentham, do hereby declare that the nature of my said Invention
is particularly described and ascertained in and by the Drawings hereunto
annexed, and the following description thereof, that is to say:-.
That the mode that I employ for excluding the water, whether temporarily
or permanently. for the purposes above mentioned. is by means of a dam,
constructed in the manner herein-after described.
1st. I form the dam cither in one piece of sufficient. extent and suitable
form to enclose the whole of the spot from which the water is to be excluded,
or I form it in several separate pieces, but in both cases in such a manner
as that the junctures between the component parts of the entire dam. or of
each separate portion of it, may be made water-tight, by caulking or other-
wise, previously to its being put in its place, and, with the exceptions hereafter
specified, it may be made to serve again for a similar purpose, without separation
of its component parts.
2ndly. I form the lower part of the whole of this dam. if it be of one
entire piece, or of each of the several portions of it, in such manner as shall be
best adapted to penetrate the ground on which it is to be placed to a sufficient
depth to prevent the passage of water under it.
3rdly. For cases in which it is requisite that so much of the dam as is
pressed into the ground, or a somewhat greater portion of it, should remain
there for the better protection of the foundation of the dam, I form it in
such a manner as to be easily separated from the upper part for this purpose.
4thly. Having formed the dam. whether entire or in parts, in some
situation the most convenient for the purpose, I bring it, with or without the
assistance of boats or other floating vessels, to the spot on which it is to stand,
and then by the application of weight, with or without the use of percussion,
I press it into. the ground to a sufficient depth; and in case of its being
formed of separate parts, the junctures between the separate parts are to be
closed up in some of the modes usually employed for such purposes, or as
hereafter described.
5th. When the dam has served its purpose in the situation in which it is
first used, it may be moved away in readiness to be employed again for a
similar purpose, the lower part having been left behind, or not, as circumstances
may require.
As to the form and mode of combining together an entire dam, or a
large portion of a dam, suitable to the different purposes in view, & under
different circumstances, the following examples may suffice.

page_text: Case 1. Where the spot from which the water is to be excluded may be
circular, as, for example, where it may be required to erect a column of
masonry to serve as the support of a bridge, the dam may be circular,
exceeding in size the intended column of masonry so much as to allow
sufficient space for the work to be carried on.
Fig. 1 shews the form of a dam applicable to this purpose. This dam is
formed of staves, as they may be called, of wood, which might be about nine
inches thick at the bottom and three inches thick at the top, connected
together on the inside by rims of cast iron, and fastened in such manner as to
admit of the dam being separated into two parts, so as to allow of its being
taken away. When the work is compleated, to the lower end is fixed a ring
of cast iron, about two feet deep, about one inch thick at the top. and as thin
as it can be well cast at the bottom, but strengthened with brackets about three
feet asunder. This circular dam is calculated to float some little height out of
water, that it may the more easily be brought over the spot where it is to be
set on the ground, where, being adjusted as to its exact situation, platforms
may be laid upon the interior rings, and weights laid upon them, whether the
materials to be used for the column or other weights, so as to press the cutting
edge of the cylinder into the ground; and when the edge shall have penetrated
sufficiently to have become water-tight in the ground, the interior water may
be pumped out, and the ground prepared in any manner that may be thought
proper, and the masonry work be proceeded with. The column of masonry
being completed so far as that the dam is no longer wanted, the two halves
of it may be unscrewed or otherwise detached from each other, so that they
may be removed without impediment from the column within. The cutting
edge of iron may also be detached, and left in the ground, if thought requisite,
or it may, together with the cylinder, be raised up out of the ground by means
of screws or other inechanical power, applied, for instance, on the column itself,
or otherwise. The parts may then be floated to a convenient place for recon-
necting them, and for adding a new cutting edge, if the first has been left in
the ground; and the dam may, as before, be employed for the construction
of another column, and so on successively.
Case 2d. Where the spot from which the water is to be excluded may
be of an oblong form, as, for example, when it may be required to erect some
distinct mass of masonry like that of the pier of a bridge, the mode of forming
and managing the dam might be the same as in the preceding case, excepting
so far as regards the supports which would be requisite for a strait-sided dam,
but which are unnecessary in regard to a circular one.
Figs. 2 and 3 shew a dam enclosing a space of about fifty-five feet in

page_text: .
length and about twenty in breadth.
Provision should be made in this case
for detaching either one side of this dam from the rest, or all the four sides
one from the other. That the strait sides and ends of this dam may be
enabled to resist the pressure of the external water, cross shores are introduced,
marked A, A, A. These shores, the upper ones particularly, may serve as
beams or bearers to support stages on which the materials for the pier may be
deposited, and for other purposes subservient to the carrying on the work.
As the masonry is brought up from the bottom, these cross shores would be
taken away, inserting previously, in lieu of them, as the work advances
upwards, short shores, as B, B, in Fig. 4, from the sides & ends of the dam,
and resting against the work itself. When it may be required to exclude the
water, for the carrying on a pier or wall projected into water for a considerable
length, the mode of forming and management of the dam might be as
specified in regard to Case the 2nd, excepting that after the first portion
of wall shall have been formed one of the ends of the dam must be either
altogether omitted, or have a vacancy left in it sufficient to receive a portion of
the wall already executed, and to which it must be made to fit water tight.
Fig. 4 shews a dam fitted to a portion of wall already executed. The
juncture of the dam to the wall may be made in any of the modes in use for
excluding water. A projection of wood C. C. Fig. No. 4, is shown at the
side of the part of the wall already built, which would facilitate the juncture
with the dam by means of or coffre dam pile. When it may be required to
exclude the water for carrying on a warf wall or embarkment, the side of the
shore itself being supported to serve as one of the boundaries of the dam, the
interior side of the dam, as well as one end, as above specified, or even both
ends, would be omitted. The ends might be made tight, one against the
wall itself, the other against the shore, in any of the usual modes, and the
longitudinal dam might be supported by shuts from the ground within. The
dams that are above described have been supposed to be single; but in some
cases, either in consequence of a less perfectly water-tight stratum of ground,
or from other circumstances, it may be preferable to make them double. A
double dam, like a single one, above described, might be formed in one piece,
so as to enclose the whole of the space, or, consequently, to form two or
more of the contiguous sides of the space, out of which the water is to be
excluded; but as it would be generally most expedient to construct in one
piece a dam of such form and dimensions as should serve to form no more
than one side of an enclosure, or even a portion only of one side when an
entire side would be of an inconvenient length, I proceed to describe a double
dam suited to form one such portion of the requisite enclosure.

page_text: Figures 5, 6, 7, and 8 shew a double dam, of about 55 feet in length,
about thirty feet high, and 12 feet broad, the structure of which should be
made sufficiently strong to resist the pressure of the exterior water acting
on one side, while the water is altogether taken away from the other. To the
bottom of this dam there is fixed a cast-iron frame D, D. corresponding in
breadth and length to the bottom of the dam to which it is fixed, projecting
from it downwards. & adapted in other respects to the penetration of the
ground, as in the instance of the lower part of the single dam.
Figures 9 and 12 shew plans, and Figs. 10 and 11 sections, exhibiting the
mode in which a cast-iron frame may be formed, the smaller round holes in
Fig. 9 being intended to receive bolts or screws to fasten the cast-iron frame
to the bottom of the dam when it is to remain fixed to it. The holes in
Fig. 11 are for to receive screw bolts to connect the several component parts
of the frame together. The long holes in Fig. 12 are intended to receive the
ends of bolts shaped like a T, and put down through the lower wooden
plate of the damn, so that being turned a quarter round the iron frame may be
held fast, or separated from the bottom of the dam when required to be left
behind. It is evident that as soon as the lower edge of this sharp frame
enters the ground, so as to become water-tight throughout, no more the water
included within it could escape, and consequently the lower part of such dam
could be made to penetrate very little, if at all, farther into the ground. To
obviate this, a pipe E, E, as shewn in Fig. 7, is laid through the bottom and
through the side of the dam, and fitted with a stopcock F. so as to allow at
pleasure the enclosed water to escape as the floating dam sinks down upon
the ground. The same Figure shews a forcing pump G, by means of which
water may be forced into this inclosure under the bottom of the dam, whereby
the raising of it up again out of the ground, when it is required to be removed,
may be the more easily accomplished.
Fig. 13 shews the manner in which four such portions of a double dam
may be set down so as to include a quadrangular space for the purpose of
constructing any detached work, as, for example, the pier of a bridge.
Letters S, S, S, S, shew four perpendicular stops fixed to the interior surface
of the end dams, so as to regulate the distance between and afford support
to the side dams.
Fig. 14 shews the manner in which three such double dams may be set down
for the exclusion of the water for the purpose of erecting a wall or pier project-
ing into the sea. An embarking wall may be carried on, under the protec-
tion of a double dam, according to the above-mentioned mode, in the following
manner: The outer side of the dam being formed by a double dam, the

page_text: same as in the former cases, and one end being joined on to the part of the
wall already built, the other end may be joined water-tight against the shore,
either compleatly by a portion of a double dam constructed in the same mode
with the others, but made shallower at the part next the shore, so as to suit
the inclination of it, or in part by such a double dam and the remaining part
in the usual manner, or, if the distance be small, the whole of this end may
be formed in the usual manner. For the purpose of excluding the water
from so extensive a place as would be required for the formation of a dock, for
example, or for the purpose of carrying on at the same time a greater length
of pier or of embarkment than it would be convenient to give to a double
dam in one piece, any such line of dam might be formed by any number
of such floating dans set on to the end of the other lengthways. taking care
in all cases when shoreing for this purpose would be inconvenient, to make the
bottom or base on which such double dam is to stand of sufficient. breadth
to enable it to resist the pressure of the exterior water. The dams themselves
may be made of wood, or of iron, cast or wrought, or of any other suitable
material and the double dams being hollow, like navigable vessels, may be
made use of as receptacles for materials, the erection of a steam engine,
lodging for workmen, or other purposes subservient to the carrying on the
work. It may be scarcely necessary to observe, that the perpendicular as
well as the other dimensions of the dams must be made conformably to the
circumstances in which they are to be used, and which, as well as the
selection of the kind of dam for each particular work, and the adaptation
of it, as well in respect of the form, which, in the instance of either the
double or single dam, may be more or less curved at pleasure, conformably
to my mode, as specified above, and exemplified in the above particular cases,
must be left to the discretion of the engineer or other person employed in the
planning or direction of any work in which these dams may be used. In
the case of dams formed in any of the manners above mentioned, as in the
case of dams formed as usual, clay or other soil may be applied to the outside
of them, whenever it may appear requisite. So, in regard to the double dams,
as above described, where the soil be such as to make it requisite, the bottom
of such double dam may be omitted, for the purpose of enabling soil of any
kind, whether enclosed in bags or not, with a due mixture of moss, sea weed,
straw litter, or other fibrous matter, to be deposited between the outer and
inner boundary of the double dam. For the purpose of enabling the juncture
between the several portions of dams set up separately to be more easily made
water-tight when in their places, I prepare, when the exact line of juncture
can be previously ascertained, a groove in both the surfaces of the dams

page_text: that are to meet, otherwise in one of them, continuing the groove down to the
lower edge of the cast-iron or other penetrating part of the dam, into which
groove so prepared either a tongue of wood may be inserted in the manner
which has been practiced in regard to coffre dams, or in some cases, with
better effect, some elastic or plastic matter, such as oakum, moss, cut straw,
with or without a mixture of earthy matter, may be rammed from the top
down to their very lowest edge.
In witness whereof, I. the said Samuel Bentham, have hereunto set my
hand and seal, the Fourth day of May, in the year of our Lord One
thousand eight hundred and twelve.
SAM BENTHAM. (.s.)
AND BE IT REMEMBERED, that on the Fourth day of May, in the year
of our Lord 1812, the aforesaid Samuel Bentham came before our said Lord
the King in His Chancery, and acknowledged the Specification aforesaid, and
all and every thing therein contained and specified, in form above written.
And also the Specification aforesaid was stampt according to the tenor of
the Statute made for that purpose.
Inrolled the Fourth day of May, in the year of our Lord One thousand