A SECURE ECONOMICAL MODE OF LAYING FOUNDATIONS, AND IN SOME CASES OF PROCEEDING WITH THE SUPER- STRUCTURE, OF WORKS OF STONE, OR OF BRICK OR OTHER ARTIFICIALLY COMPOSED MATERIALS, PARTICULARLY APPLICABLE TO THE PROJECTION OF WHARFS AND PIERS INTO DEEP WATER, TO THE CONSTRUCTION OF BRIDGES, AND THE FORMATION OR IMPROVEMENT OF HARBOURS, AS WELL AS TO THE ERECTION OF HEAVY BUILDINGS ON BAD GROUND
Year: 1811

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 Second day of April,
in the fifty-first year of His reign, give and grant unto me, the said Samuel
Bentham, my exors, adññiors, and assigns, His especial licence, full power, sole.
privilege and authority, that I, the said Samuel Bentham, my exors, admors,
and assigns, during the term of years therein mentioned, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "A SECURE ECONOMICAL MODE OF
LAYING FOUNDATIONS, AND IN SOME CASES OF PROCEEDING WITH THE SUPER-
STRUCTURE, OF WORKS OF STONE, OR OF BRICK OR OTHER ARTIFICIALLY COMPOSED
MATERIALS, PARTICULARLY APPLICABLE TO THE PROJECTION OF WHARFS AND PIERS INTO
DEEP WATER, TO THE CONSTRUCTION OF BRIDGES, AND THE FORMATION OR IMPROVEMENT
OF HARBOURS, AS WELL AS TO THE ERECTION OF HEAVY BUILDINGS ON BAD GROUND;"
in which said Letters Patent there is contained a proviso obliging me, the
said Samuel Bentham, by an instrument in writing 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 enrolled in His
Majesty's High Court of Chancery within six calendar months after the date
of the said recited Letters Patent.

page_text: 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,
and in what manner the same is to be performed, is described by the
Drawings hereunto annexed, and the following description thereof (that is
to say):-
To whatever depth the foundation of any structure is to be laid under
water or ground, first I combine together, above ground or above water, either
over the place into which the, foundation is to be forced or elsewhere, stone or
brick or other artificially composed materials, with or without introduction of
wood or iron in the bottom, or for ties, as occasion may require, into sometimes a
number of distinct masses, and sometimes into one entire mass, which, when
put where they are or it is to remain, shall constitute the foundation or lower
part of any structure, together with more or less or even the whole of the
structure. Secondly, I place those masses or this mass in their or its required
situation without the need of clearing away the water or ground to the depth
at which they or it are or is to be laid, and in case of works under water,
without the use of any cassoon or dam composed of wood or other materials,
to enclose the work while building, conveying to the spot where it is to be
deposited or depositing. Thirdly, I press the foundation masses or mass
into the ground, either in its natural or in its artificially-prepared state,
whether under water or not, with a degree of pressure such as shall be deemed
sufficient to prevent the further injurious yielding of the ground when the
superstructure shall be built up and be applied to use, and in giving this
pressure previously to the proceeding with that part of the superstructure in
regard to which any further sinking of the foundation would be injurious. As
to the formation of these masses, they may be either solid or hollow; or, though
hollow at first for the convenience of floating or otherwise removing them
from place to place or of depositing them, they may afterwards be more or
less filled up. The exterior may be of one material for lightness or for
appearance sake, and the interior for cheapness or for strength, of some
different material, as; for instance, the mass may be first formed of a thin
bottom, and then walls of brick, for the sake of lightness. The walls may
afterwards be thickened, or the interior be entirely filled in with stone, with
bricks, or with other artificially composed materials. Wood and iron may be
employed as ties, as well as for beams, rafters, or any part of the superstructure
of these masses, as is usual in building of which the walls are of masonry or
brickwork. The masses may be of any size or shape, from the depth.
supposing them solid, of only a few bricks, and of the horizontal dimensions of
a square of nine inches, being the length of an ordinary brick, or even less, to

page_text: the size and shape, if hollow, adapted to contain the largest ship or even
several ships at a time, so as to form in one mass a dock or a lock or any
other more extensive work. As then the particulars of these masses may
vary so much, the selection, in the instance of each particular work, of the
most suitable form, material, and mode of proceeding must consequently be
left to the engineer, architect, mason, bricklayer, or other workmen to whom
the management of the work may be entrusted.
I proceed to specify, in the way of example, some particular shapes and
dimensions of the masses, and some of the modes which may be employed for
the conveying them to their places, depositing them and pressing them down,
which shall be metable to some works of considerable importance and variety,
so that a skilfull engineer, architect, mason, or bricklayer, assisted in regard
to the management of the masses that are to float by some one conversant in
the management of the floating bodies, may be enabled, by the consideration
of these examples, to vary the construction of the masses, and the mode of
proceeding in the use of them, according to the nature of the particular
work he has to carry on, and according to the circumstances under which it is
to be executed.. Supposing that in a situation where at low water the depth
of the water is twenty-four feet, and consequently where a ship of the line
may at all times lie afloat, and where the ground is of such a nature as that
within a depth of from five to ten feet from its surface it is deemed incapable
of bearing a solid wall with the weight of the several articles that may come
to be deposited upon it, it be required to construct a wharf wall, it may be
proceeded with, according to my mode, as follows:-
First, let it be ascertained, by means of a probe or otherwise, to what
depth, by a known weight pressing upon a base of known superficial extent,
the ground in the scite of the proposed wall will be penetrated. Let the spot
in question be then levelled, where requisite, by means of an engine for
digging under water or otherwise; and if in the intended line of wall the
eveness of the ground be interrupted by any matter too large to be removed,
such, for instance, as portions of an old ship, let the ground in such parts be
raised somewhat above the most prominent obstacles by depositing stones,
shingle, gravel; or other such materials, with a mixture, where convenient, of
seaweed, and with the addition of some lime or other cement, if it be thought
requisite, to cement these materials together. Secondly, let hollow masses,
twenty-one-feet square at their base, with perpendicular sides, be prepared on
a platform in a situation where the tide, at the time of high water, rises
sixteen feet above the platform. Let them be built of brick, cemented with
Roman cement, bottom and sides, so as to be water-tight, of the form and

page_text: dimensions shewn by Figure 1 up to the height of twenty feet, letting in
water on the rise of the tide, by means of a syphon or otherwise, to prevent
their floating, and running out the water by the same means as the tide falls.
Thirdly, let the masses, when so far built, remain a short time on the platform,
a week or more, so that the cement may indurate; then let the water to be
drawn or pumped out of them, so that by their buoyancy they may float off
the platform; then, having passed ropes or chains round them and under them,
and having put up a pole in each corner for the more convenient managing
them afloat, let them be taken immediately over the spot where they are to
be deposited, or previously to some other place, where, an account of smoother
water or better protection, or on other accounts, they may lie more conve-
niently and let them be built up to the height of thirty-five feet, beginning,
as soon as the buoyancy will admit of it, to thicken and strengthen the
bottom and lower part of the sides with additional brickwork, and filling in
shingle, rubble, or other materials, mixing them with mortar or lime, so that
these materials may indurate and give strength to the bottom. Fourth,
having floated one of the masses as exactly as possible over the spot on which
it is to be deposited, let water into it by means of syphon or otherwise, so that
it may sink to the ground; when there will remain perhaps about eight or ten
feet above water at the time of low water. Fifth, having prepared a vessel
laden so that the total weight of the vessel and lading shall be somewhat more
than the supposed weight of the additional superstructure which will rest upon
one mass, together with that of the heavy articles which the wall, when
finished, may be supposed liable to bear, let this vessel be brought over the
mass at the time of high water, and be placed so as to ground upon the mass
when the water falls, having previously, according to the shape of the bottom
of the vessel, made some preparation, by laying timbers on the mass or otherwise,
to cause the pressure to be sufficiently distributed over the surface of the mass,
and observing, in case the mass should have rested out of the level, to place
the vessel so as to press most on the highest side of the mass. By the time
of low water, the vessel having rested entirely on the mass unsupported by the
water, the mass will have been pressed down more or less; and if it be mate-
rially out of the perpendicular, or other direction more desirable, let the
vessel be removed during another high water to another part of the mass, so
as to bring it into the proper direction, and let this operation be repeated until
the position of the mass is corrected. If, however, from some unfavourable
accident or otherwise, the mass should not by this means be brought into its
required situation, let the water, during the recess of the tide, be pumped out
of the mass, so that it may be made to float again, which may be easily done

page_text: unless the bed on which it rests be such as to exclude the water from
insinuating itself under the bottom, and let the bed itself be raised or leveled
in any required part, so that on depositing and pressing the mass again it may.
rest in the desired situation. In the same manner let the other masses be
brought over and deposited in their respective places. For the more easy
adjustment of one mass in a line with the others an indenture may be formed
on the side of one mass, and a corresponding projection in the contiguous side
of the other mass; or a perpendicular groove may be formed on the sides of
each mass, corresponding with similar grooves in the sides of the contiguous
masses, into which grooves pieces of timber, in the form of folding wedges,
may be inserted during the time of placing one mass against the other, after
which the timbers may easily be taken out of the spaces they occupied, as well
as the joints or intervals between the contiguous masses may be filled up with
brickwork and grout, rubble work, or other materials. The data, dimensions,
and materials described in this example being given only as the illustration of:
the general method, it is not meant as being essential to the execution of the
wharf wall upon my plan that the mode as above described should be minutely
followed; but, on the contrary, in my mode work for a similar purpose may
be executed in any depth of water, on any soil, of any dimensions and of any.
materials, such as brick, stone of any kind, natural or artificial, or of any
mixture of the smaller stones, such as shingle or gravel, artificially combined,
together with Roman cement, mortar, or other indurating material, taking
care in each instance to calculate the weight of the materials of each intended
mass previously to its construction, as also the quantity of water it will.
displace, so that by duly proportioning the thickness of the bottom and walls
to the quantity of water the mass will displace, its buoyancy may be insured,
taking care that the work be executed so as to be water-tight. When
the masses forming component parts of the foundation have been depo-
sited and pressed with the requisite pressure into their places, which,
pressure may be applied either gradually or suddenly, and be made to.
continue a longer or shorter time, according to the nature of the soil, the,
completion of the superstructure of the wall may be effected either by con-
tinuing these masses up distinctly without bonding the work of one with
that of the other, so that in case of any unprovided-for occurrence one
mass may be at liberty to settle farther without the other, or the work may
be carried up in the usual way, bonding that over one mass with that over
the adjacent one, so as to unite the whole together, and thereby the better
insure against any partial settling from partial causes; or, if it should be
thought more advisable, with a view to avoid the delay of tide work, or for

page_text: any other reason, hollow masses may be prepared of an heighth to reach from
the top of the foundation masses, up, in some cases, as high as the wall is
required to be carried, and these masses may be deposited upon the foundation
ones, so as to complete the work up to its height, taking advantage of the
recess of the tide to deposit a layer of mortar or other cement upon the upper
surface of the lower mass, so as to receive the lower surface of the upper one,
and this either so that each of these upper masses should coincide in dimen-
sions and rest exactly over one of the lower ones, so as to extend over two
or more of the foundation masses to form bond. The masses, whether under
or upper ones, may either have their walls thickened after they are deposited
or they may be entirely filled up; or they may be made to serve for cellars or
store rooms, or other useful purposes, having been prepared of suitable forms
and dimensions for any such purpose that may have been in view. In the
case of forming a mole or pier, with a view to its acting as a breakwater
to the waves of the sea, while at the same time it is desired that the tide or
current should pass with as little interruption as possible, instead of forming
an entire pier of masonry for such a purpose, or by throwing down stones or
materials of any kind to form a mound which would totally interrupt the
passage of the current below, as well as oppose the violence of the waves"
above, two or more rows of distinct masses might be deposited in the direction
of the intended breakwater, leaving in each row of masses an interval between
mass and mass for the free passage of the tide or current, but placing the
masses of the interior row opposite to the intervals of the exterior row, so that
the whole together should form a complete impediment to the direct action
of the waves, yet allowing the tide or current to pass below between the
masses, even in a contrary direction. Supposing in this case the masses to
be cylindrical, say fifty feet diameter, and the intervals between mass and
mass in the row also fifty feet, then by two such rows of masses, those of one
row not more than twenty-five or thirty feet distant from those of the other
row, the impediment thereby afforded to the waves, whether coming at right
angles or oblique to the direction of such a breakwater, would in most cases
be sufficient for the purpose of insuring smooth water within the space pro-
tected by these masses, while the passage of the tide or current would in no
part of the pier be diminished more than half. But with a view to the
affording a more complete impediment to the action of the waves, and at the
same time a still less impediment to the course of the tide or current, masses
might be constructed and deposited of a form suited to serve as foundation
masses, in the manner of the piers of a bridge, and superincumbent masses
prepared of a form suited to the extending from one foundation mass to the

page_text: other might be deposited, resting each end upon a foundation mass, forming all
together, as it were, a bridge, but differing from an ordinary bridge, inasmuch
as with a view to the not caposing the under surface of the superincumbent
masses to the violence of the waves, and to the affording as compleat a pro-
tection during low water as at other times, the lower part of the continuous
structure should be kept so low as to be always under water, even during
low water. These superincumbent masses, having been made, at least in the
first instance, hollow, with a view to the floating them on to the others on
which they are to be deposited, if it should not be deemed necessary after-
wards to fill them up to afford greater strength or weight, might be formed
with sloping sides towards the side exposed to the violent action of the sea,
but with perpendicular sides towards the still water, and might be made to
afford wharfage and a great quantity of enclosed space, applicable to various
useful purposes. Supposing it be desired to build a bridge where the ground
on which the piers are to stand has been found, by probing as well as boring,
to be of an uniform tenacity, equally yielding, or when it can be made so by
the deposit of any material; let the foundation of each pier, with more or less
of the superstructure, at least so much as to reach above low water, be of one
single mass, and let it be floated, deposited, and pressed in the same manner
as is described in regard to the wharf wall. Should the ground-be of unequal
degrees of firmness, or if on any other account it should be adviseable that the
foundation of each pier, with more or less of its superstructure, should be
formed of any greater number of distinct masses, either contiguous to or more
or less distant from one another, let each pier be proceeded with in distinct
masses, as in the case of the wharf wall, but varying the forms of the masses
as may be most eligible for the particular purpose of the pier. In cases
where the bridge is to serve the purpose of a dam, with a sluice or a lock
between any of the piers, let a mass be constructed of such form and dimen-
sions as shall comprehend at least all the under-water part of the-whole of
the sluice or other work requisite between the piers, together with a part,
say half, of each of the piers, one on each side of the sluice; the bottom of
which sluice or lock may be in the form of an inverted arch, or otherwise; but
as a mass so shaped would form only the bottom and two- sides of the four
requisite to form a cavity, by means of which the mass might be made
buoyant, let the two other sides or ends be formed in a temporary manner
across the space between the half piers, one at each end, so as to keep out
the water while such a mass should be building, or at least whilst it should
be transporting to the place in which it will be deposited, and so that these
temporary ends shou'd afterwards be readily taken away. These temporary

page_text: ends might conveniently and economically be formed of two floating dams,
which being analagous in their use to floating dams employed instead of gates
to keep the water out of docks, might be made on the same principles, or
otherwise; and if all the arches of a bridge or dam were made of the same
size, these two floating dams would serve, not only as the temporary sides of
the foundation masses for forming all the spaces between the piers, but they
would afterwards serve to exclude the water from any of these spaces during
the examination, the adjustment, or the repair of the sluices or other work
that might be requisite within these spaces. In a similar manner sluices or
locks may be constructed in other situations than that of forming, part of a
bridge, when the perpendicular walls, instead of forming halves of piers, may
be made to join into walls of an embankment, or of a basin or canal. In
like manner a dry dock for the reception of one or more ships of any size
may be constructed, excepting that in this case the head of the dock would
probably be composed of the same materials as the sides, and only one floating
dam or other temporary boundary would be required for one of the ends of
the mass, which might be the same dam or gates that would be requisite
afterwards for the exclusion of the water from the dock when in use.
For the forming an embankment in a situation where there is not, and
where it is not required that there should be, a depth of water of more than
eight or ten feet, where the ground is uniform, and, if not level, such as may
easily be made so by a digging engine or otherwise, and where cellar room,
storehouse room, and habitations are wanted as near as possible to the water,
masses for an embankment under such circumstances may be built of any suit-
able dimensions in the mode exhibited by Fig. 2, so as when deposited to
form at once fifty or one hundred feet or more of embankment, the expence
of which would little exccede that of a building of the same size constructed
elsewhere for the other purposes to which such a mass would be at the same
time applicable. If it be required to stop the passage of a great body of
water, as in the case of damming up a river, masses may be prepared of the
requisite depth, according to the situation they are respectively to be deposited
in, and the bed may be prepared in a manner suited to their settling into
the ground water-tight, and the sides being prepared with or without corre-
sponding indentures, and with or without the interposition of some com-
pressible or elastic substance, they may be brought together and deposited
at the time of still water, whether high or low water, as best suited to the
purpose; and by placing them in a line somewhat curving towards the side
from which the pressure will come, they may, as soon as a difference of level
occasions a pressure, be forced by that pressure close together, and into the

page_text: banks against which they are required to abut. As to the general means
of rendering masses for the before-mentioned purpose buoyant and strong,
it is evident that in point of buoyancy nothing more is required, as before
observed, then that they should be of a capacity in proportion to the weight of
materials employed, so as to displace a quantity of water sufficiently great for
its weight to exceed that of the materials used. So, in regard to the giving
the requisite strength, the force with which water presses at different depths
is well known, as are various means of using different materials to the best
advantage to resist that force; but as the forming the sides as well as the
bottoms of the masses in the first instance as light as possible (however they
may be strengthened by additional materials afterwards) is a matter of more
importance than in buildings of the usual kind, I have to observe that one
mode of very extensive application for giving such work great strength with
little weight is the making the walls of the masses double with cellular par-
titions, and the bottoms at first very thin, but strengthened by ribs of stone or
brickwork, which may be made in some cases no thicker than the thickness of
an ordinary brick, if the cement be strong, in the manner shewn by Figures 2
and 4. Bottoms of masses so constructed, however great their superficial
extent, may be advantageously built on platforms not more than 5 or 6 feet
below the level of high water, since by that means the work would be but
little interrupted by the tide; and they might also be constructed on a platform
composed of logs of timber floating on the water, and as soon as the sides of
the masses were carried up sufficiently high to make them bouyant the logs of
timber might be drawn from under them, or cellular bottoms may be formed
by preparing first small portions of this bottom, as represented by Figure 4,
which portions being applied together side by side when floating in the water,
and held by some temporary means close together, grout may be applied in
the interstices at the place of juncture, so as to cement the portions together,
after which the ribs or walls dividing the bottom into squares or other shaped
compartments may be raised upon over the junctures, so as to cement these
several portions more firmly together, and the work may be proceeded with
as if the whole bottom had been built ashore, and united together in one mass
in the first instance.
The masses for the above-mentioned purposes, being all of them structures
in water, have been spoken of as hollow, a mode of forming them which
seems in general preferable for waterworks, on account of the facility of
floating them about, and of raising or lowering them by the rise or fall of the
tide. I have to observe, however, that according to my mode, masses for
such purposes might, in many cases, be made solid, and being formed over

page_text: the spot on which they are to be deposited, they might be supported by
tackles or otherwise during their construction, and be lowere down into
the water as their structure is proceeded with, or they might be formed
on land and slid down on a kind of railroad or otherwise in an inclined
direction, one over the other, so as to form a progressive projection from the
land into the sea, or, although formed elsewhere, they might he floated
between vessels or otherwise to the place where they are to be deposited,
They might also, be made hollow, though without being water-tight, and be
floated to their places, or even be built afloat supported by buoyant bodies of
various kinds, and in masses of various shapes, particularly in regard to cylin-
drical masses. A cylindrical vessel of wood, hooped together like a cask,
might be applied on the inside of a cylindrical mass, by means of which
interior support, with or without the addition of some farther support applied
on the outsides of the mass, such a mass might be thus built and deposited,
and afterwards be pressed, without the need of making it water-light, or
without the mass itself having any bottom.
In the case of a wall, or other erection for an embankment or for other
purposes, being to be constructed. on ground which, though dry at the time of
low water, is considerably, say five or six feet, under water at the time of
high water, the foundation in that case may be laid in distinct masses built
upon the spot contiguous to one another, or not of large dimensions; or
small, like piles, to such an height as that a flat-bottomed vessel, loaded with
the requisite. weight, may be grounded upon them, whereby the stability of
the work may be insured, before the superstructure.is proceeded with, with the
same case as if the work had been more under water.
In regard to the masses proper for forming the foundations of structures
on land, in the case of the ground being such as, though at the surface it be
unfit for the support of the structure, yet, there being a firm stratum at no
great depth, but varying at different parts under the scite of the structure,
supposing it be required to make the structure rest on piers, on which, by the
turning of arches from one to the other or otherwise, an entire support for the
superstructure. may be formed at the surface of the ground or above it, for the
forming of those piers let distinct masses of stone, brickwork, or other suitable
materials be built up, standing first on the surface of the ground, sinking
down more or less during their construction, and when built up to such height
from their bottoms as may be supposed sufficient to reach to the solid ground,
let weights of any kind, such, for instance, as iron ballast, be laid upon them,
to press them through the yielding soil on to or into the bard stratum,. the
foot of each pier being, if requisite, adapted in shape to penetrate the soil,

page_text: with or without a shoe of cast iron or other materials particularly suited to the
purpose; or let this pressure be. assisted or be given wholly by percussion;
applying some intermediate substance upon the head of the piers for the
beater to strike upon, with such other precautions as to the weight and velocity
of the beater as are known to be suitable to the forcing down brittle materials
without injury. In cases where the stability of the structure is made to
depend on the extent to which the foundation is spread for procuring the
requisite support, having estimated the weight which a given extent, say a
yard square, of the foundation under the different parts of the building is
required to sustain, and having probed the ground to form some opinion of
the depth to which a square yard of surface must be pressed before it will
support that weight, let distinct masses be built up perpendicularly on bases of
the extent of, say, a yard square, contiguous to one another over the whole scite
of the foundation, and up as high as it is supposed they will be pressed into
the ground, cach mass respectively more or less, in consequence of any
variations there may be in the nature of the ground, or in the weights to be
supported by different parts of the foundations, then let the requisite weight
be applied upon each mass respectively, or if the means be easy on several
contiguous ones at the same time, or, as before, let percussion be employed
either to a degree calculated to be at least equal to that of the requisite pressure
by weight, or let weight and percussion be jointly employed until the whole of
the distinct masses constituting the foundation have been submitted to the
requisite pressure. In cases where the pressure which different parts of the
foundation will have to support is very different, as that of the foundation for
the steeple of a church compared to that for the lighter parts, let the mass or
masses forming the foundation for the heavier parts be always distinct from
those for the lighter parts, and let them be pressed with a proportionably
heavier weight. These masses, when placed contiguous to one another in a
proper direction one with regard to the other, may then be pressed down, and
when pressed down they may be connected together before the superstructure
is proceeded with; and in some cases it may be expedient to make these
masses no larger than piles of wood, to which, however, they might be
preferable, as being of cheaper and more durable materials.
In witness whereof, I, the said Samuel Bentham, have hereunto set my
hand and seal, this First day of October, in the year of our Lord One
thousand eight hundred and eleven.
SAM BENTHAM. (L.S.)

page_text: AND BE IT REMEMBERED, that on the First day of October, in the
year of our Lord 1811, the aforesaid Samuel Bentham, Esquire, 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 First day of October, in the year of our Lord One
thousand eight hundred and eleven.