AN IMPROVEMENT IN PREPARING OR MANU- FACTURING SUBSTANCES FOR THE FORMATION OF HIGHWAYS AND OTHER ROADS, AND WHICH SUBSTANCES WHEN SO PREPARED ARE APPLICABLE TO OTHER USEFUL PURPOSES
Year: 1820

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ABRAHAM
HENRY CHAMBERS, of Bond Street, in the County of Middlesex, Esquire, send
greeting.
WHEREAS His most Excellent Majesty King George the Fourth did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Eighteenth day of
March, in the first year of His reign, give and grant unto me, the said
Abraham Henry Chambers, my exors, adñiors, and assigns, His especial
licence, full power, sole privilege and authority, that I, the said Abraham
Henry Chambers, my exors, admors, and assigns, should and lawfully might
make, use, exercise, and vend; within England, Wales, and the Town of
Berwick-upon-Tweed, my Invention of "AN IMPROVEMENT IN PREPARING OR MANU-
FACTURING SUBSTANCES FOR THE FORMATION OF HIGHWAYS AND OTHER ROADS, AND
WHICH SUBSTANCES WHEN SO PREPARED ARE APPLICABLE TO OTHER USEFUL PURPOSES;"
in which said Letters Patent there is contained a proviso that if I, the said
Abraham Henry Chambers, shall not particularly describe and ascertain the
nature of my said Invention, and in what manner the same is to be per-
formed, 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 six
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.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Abraham Henry Chambers, do hereby declare that the aforesaid improve-
ment in preparing or manufacturing substances for the formation of roads,
and for other useful purposes, consists in the burning, calcining, and vitrifying
of certain earths or earthy materials, and of applying the same when so burnt,
calcined, or vitrified in a particular manner, herein-after set forth and described,
for the making and repairing of roads and footpaths, and also of the applica-
tion of such materials to the other new and useful purposes also herein-after
named.
The earths which I select for this purpose are clay, loam, or marl, or any
other earth, by what name soever it may be distinguished, as will not fall to
powder or burn to useful lime by the heat of the kiln, but will indurate and
vitrify by such heat, although a small portion of lime or lime stone will not
injure the process. This earth is to be burnt in kilns, which should be
built as near to the road to be made or repaired and to the earth to be burnt
as possible, for the obvious reason of avoiding all expence of horse or cattle
labour in removal or carriage, which is one of the principal features in the
value of my new system of road-making, no such expence being required
except for the cartage of the necessary fuel and the lime for grouting, as
herein-after mentioned. To explain this, I now state that my Invention is
not meant to supercede the use of stones, gravel, or other good and hard
materials. when the same are found upon the spot, and are, consequently,
cheaper than any other that can be used; but it applies most particularly to
those stiff, cold, loamy, or clayey districts in which no good and sufficiently hard
materials for roads are to be obtained but by a long conveyance at great
expence. Its advantages are therefore obvious, because by its means road
materials of the very best kind are produced upon the spot where they are
most required at a comparatively small expence, for a road running over a tract
of clay or other soil of fit nature to burn and vitrify may by my process be
repaired and improved out of its own materials. The means which I use and
recommend to be resorted to in such cases are to dig a ditch or trench of
about two feet in width on one or both the sides of the road, and parallel
thereto or running lengthwise with the same, the depth of such ditches or
trenches being made sufficient to drain the road. The soil dug out from such
trenches is to be piled up or placed upon the edges of the same, either upon
the road or, if room should be wanting in any convenient situation, the base or
bottom of the pile or heap being about three feet wide, and in this state it is
to be left until it becomes sufficiently dry by exposure to the air to be carried
to the kiln to be burnt or vitrified, during which time the road itself and the

page_text: part upon which the excavated soil rests will be considerably dried by the
operation of the side drains thus formed. The kiln or kilns for burning, cal-
cining, or vitrifying the said materials are to be formed of the same excavated
clay or earth; & when a new road is to be formed they should not be more
than about ten poles or fifty-five yards one from the other in order to prevent
the encreased price of wheeling the materials to and from the kiln. The kilns
may be made of any length, but should not exceed six yards in width at the
base (inclusive of the thickness of the side walls), which for the first three feet in
height should be from two feet and an half to three feet in thickness. The object
of confining the kilns to this breadth is for the convenience of protecting or
covering them with sail cloth, padded hurdles, or boards, in case of wet seasons
or sudden rains, which is of essential importance to guard against until the kiln
is charged with at least four or five feet of fuel and materials well heated,
when it may be considered as tolerably safe. The materials and fuel in a kiln of
this description may be made five or six feet high; and the manner in which
I dispose them, as well as the construction of the kiln, are described as follows:
The kiln consists of a back and front and two end walls formed of clay
or earth aforesaid; thro' the back and front walls fire holes of about nine
inches high and a foot wide are made lower than the surface of the internal
earth or flooring of the kiln, and at about six feet apart, and a similar fire hole
is made thro' the center of each of the said end walls. Trenches or channels
of about a foot wide and nine inches deep are dug or formed in the bottom of
the inside of the kiln from one fire hole to that opposite to it in the front and
back walls, and a similar trench or channel is formed through the middle of
the kiln from one end hole to the other, so as to cross all the before mentioned
trenches or channels at right angles. Wood, coal, coke, culm, slack, or cinder
ashes (known in London by the names of soil and breeze) may be made use
of as fuel, but in all cases faggots must in the first instance be applied to set
any of these combustibles on fire; and these faggots are to be applied in the
trenches or channels aforesaid, which are to be quite filled with them, the
brush ends of some of the faggots being left projecting thro' the fire holes
aforesaid; in this way a kiln of twelve yards long and six yards wide (in-
cluding the walls) will require about a hundred dry faggots; over these large
wood or other fuel is to be placed, and the whole covered with about two feet
in thickness of clay or other fit soil, dried as aforesaid by exposure to the sun
and air. Upon the stratum of two feet in thickness is again to. be added such
a quantity of hard wood or other fuel as, when thoroughly ignited, will be suffi-
cient to burn, calcine, and vitrify the principal part of the contents of the kiln,
which are to be applied in lumps of various sizes such as the materials will

page_text: generally form; but all dust or powder created by the drying must be thrown
on one side (for damping the fire, as is herein-after mentioned), since such fine
stuff would impede the action of the fire by closing all interstices, and thereby
checking its draught. Kelp, fern, the cuttings of vines, refuse hay, and such
other vegetables as produce alcali on being burnt, may also be mixed with the
soil to assist in its vitrification, or even salt, barilla, potash, or soap ashes may
be applied for this purpose wherever they can be obtained on sufficiently
low terms. Should the work or situation require a more extensive kiln
than is herein-before described, such kiln may have another portion of like
dimensions added to it either in the front or at, the back, in which latter case
the original or first back wall becomes only a partition wall, and need not
be more than eighteen inches thick. And if further addition be found
requisite, the same operation may be repeated by extending the end walls six
yards more, and making either another partition wall of eighteen inches
thick, or a final one of two feet and an half or three feet in thickness. These
additions, however, must all be made before the kiln is lighted, and by their
means kilns of any extent may be formed for such situations as demand them,
taking care in all cases where partition walls are formed to leave holes like
windows of about eighteen inches square at the height of about fifteen or
eighteen inches above, the lower fire holes, and to place them over the same
for the passage and communication of the fire, which should be lighted at all
the holes at nearly the same time, observing to light those to the Jeward side
of the kiln the first. The produce of a kiln can scarcely ever be all burnt,
calcined, or vitrified, so as to be equally hard and of the same description, for
this will depend on the nature of the soil to be acted upon, the quantity and
quality of the fuel, the strength and direction of the wind acting upon the fire,
and other circumstances, so that materials differing in quality from a place
brick to the hardest vitrified substance will be produced by the burning of each
kiln, and these require to be assorted; and they are easily distinguishable from
each other by their colour and hardness. I call the red materials burnt the
bright crimson, calcined,-the externally blackish red tho' internally dark purple
and honey-combed like pumice stone, fused,-while that part of the material
which is perfectly vitrified has a blackish green grass-like appearance; besides
these, a portion of burnt clay, ashes, and dust will always be produced, which,
tho not applicable to road-making; are nevertheless highly valuable as a
dressing for land, so that there is nothing in this process. that may not be
made available in reduction of the general expence. Indeed a certain quantity
of ashes and dust are unavoidable, because when the raw. materals intended. for
vitrification are all applied; and the fire has passed through to the top, it becomes

page_text: necessary for the completion of the process that the fire should be damped or
stopped down, which is effected by the small dusty particles produced by the
drying and removal of the materials, and which small stuff was herein-before
directed to be laid by for such purpose.
Having described my method of digging out, and digging out and drying, the
clay or other earth, with the mode by which the kiln or clump may be pro-
tected from rain in order to obtain vitreous matter and hard substances for
road-making, I shall proceed to detail and describe the several useful purposes
to which the said materials when produced may be applied, and in which
I claim an exclusive right under my aforesaid herein-before recited Patent,
and these are,first, to the scientific construction of public highways and
other roads; secondly, to under-draining or land-ditching; thirdly, for making
garden walks, paths, and roads in pleasure grounds; fourthly, for rick bottoms,
bottoming of barns, stables, cowhouses, pigsties, and all farming buildings;
fifthly, for bedding on which pavements may securely rest; sixthly, for moating
round all buildings and wharfs near the water side; and, seventhly, for a
substitute for ashes or sand, in making mortar or pozzolana..
1st, as to the scientific construction of public highways and other roads:-
Roads made under my Patent are divided into three distinct strata, being: first,
an impervious flooring or foundation; 2ndly, a middle stratum, being the body
of the road; and, 3dly, the exterior covering or surface of the road. Pieces
of from four to six inches square of the hardest matter produced from the
kiln are employed in making an impervious flooring or foundation; these,
tho' very irregular, are placed as close as possible to each other; upon a level
bed, formed of the small burnt or calcined materials which will always be
found on opening the kiln. The intervals between the large masses are to be
filled up with smaller portions, over which are scattered fragments that
fill up the vacancies, and over these are sifted finer parts, until, by raking
and beating down, the floor is made levil, when the whole is grouted together
with hot lime and water, and rendered impervious to the rain falling on its
surface, which, by a due convexity, is carried off laterally into drains running
parallel to the line of road, and discharging themselves into the side ditches.
There are also under drains made from one foot to fifteen inches below the
surface of the impervious flooring, and these, as well as the side drains just
mentioned, are completely (not partially) filled up by small portions of the
calcined materials, screened, so as to free them from dust or small matter,
and their effect will be not only to prevent all chance of lateral absorption of
water into the road, but to receive and lead off all the rain that may fall on or

page_text: percolate through its surface. The middle stratum or body of the road is made
with the fuzed and calcined materials, so reduced as to pass through meches of
three inches square, whilst the covering or surface is constructed with the
smaller parts of the hardest materials, assisted by a portion of gravel or ballast,
and rolled down with a heavy roller; the great irregularity in the shape of the
vitrified, fuzed, or calcined materials, of which the foundation, body, and surface
of my roads are composed form such a system of resistance to the superincum-
bent weight as to give to every part of their solid contents the quality and
strength of a arch, which, resting on a substratum of clay, preserved in a dry
state, and sustained by the causeways or sides of the road, is capable of
bearing up without depression any weight allowed by law to pass over its
surface.
Secondly, I claim also the exclusive privilege and right in the use and
application of vitrified, fused, calcined, or burnt clay, or other earth (the latter
being so much burnt as to be incapable of absorbing water) in the filling up
of drains, called under drains or land ditches. These are to be completely filled
from the bottom up to the top or shoulder, made by the usual triangular spade
or tool, with pieces or fragements of the substances. The insides of the
drains are thus supported, and are prevented from scaling off and filling up the
cavity of the drain, whilst the extreme hard sharp angular points of all the
particles preclude the passage of moles, which frequently pass through under
drains partially filled with pebbles or other stones.
Thirdly, I claim the exclusive right in my said Invention for the covering of
towing paths by the sides of canals and rivers, garden walks, roads, and paths
thro' pleasure grounds.
Fourthly, I likewise claim the exclusive application of my Invention for the
bottoming of ricks and stacks of hay and corn; bottoming and foundation
(whether grouted or not) of barns or granaries, stables, cow-houses, pigsties,
and all other farming buildings, to prevent the boroughing, breeding, and
harbouring of rats and other vermin.
Fifthly, I claim also the exclusive right of applying my Invention of a
grouted flooring of vitrified, fused, or calcined clay or other earth to the
bedding on which the streets of London and other places may securely rest,
and the constant depression and want of repair in the coach-way pavements be
effectually prevented.
Sixthly, I also claim the exclusive right in the application of mysaid
Invention to the moating of wharfs, warehouses, and other buildings, by
filling up an internal space in the external walls, whether the said space

page_text: be grouted with lime and water or not, for the purpose of preventing the
boroughing and breeding of rats, and preventing their access to other parts of
such or other buildings.
Seventhly, I claim likewise the exclusive right in the application of my
vitrious fused or calcined substances to the manufacture of British pozzolana,
and for the purpose of making mortar with hot or quick lime of a very superior
quality, in consequence of all the materials being non-absorbent of water, their
extreme hardness, irregularity of shape, and being wholly destitute of any
earthy matter of the least solubility in water.
Nowithstanding I have been thus particular in describing the formation
of the kilns, and the method of preparing and using the materials, yet I do
not bind myself to the particular form, dimensions, and construction of such
kilns, nor the materials of which they may be constructed, since the great
object is, to obtain materials in the state of nearest approximation to vitri-
fication; and although the process. I have described will answer the purpose,
yet if the same end is produced by other means, and the materials are
used and applied as herein-before mentioned, I consider such production
and use as appertaining to and being covered by my aforesaid Patent.
In witness whereof, I, the said Abraham Henry Chambers, have here-
unto set my hand and seal, this Eighteenth day of September, in the
year of our Lord One thousand eight hundred and twenty.