A NEW PRINCIPLE ON WHICH BRICKS, STONES, OR ANY OTHER BUILDING MATERIALS WHICH MAY BE SUBSTITUTED FOR THOSE ARTICLES, MAY BE SO FORMED AS TO BE APPLIED WITH PECULIAR ADVANTAGE IN THE ERECTION OF WALLS AND IN THE CONSTRUCTION OF ARCHES
Year: 1795

page_text: CARTWRIGHT'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDMUND
CARTWRIGHT, of Doncaster, in the County of York, Master of Arts, Clerk, do
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
Westminster, the Fourteenth day of April, in the thirty-fifth year of His
reign, did give and grant unto me, the said Edmund Cartwright, my executors,
administrators, and assigns, His special licence that I, the said Edmund Cart-
wright, my executors, administrators, and assigns, during the term of years
therein expressed, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick-upon-Tweed, my Invention
of "A NEW PRINCIPLE ON WHICH BRICKS, STONES, OR ANY OTHER BUILDING
MATERIALS WHICH MAY BE SUBSTITUTED FOR THOSE ARTICLES, MAY BE SO FORMED AS
TO BE APPLIED WITH PECULIAR ADVANTAGE IN THE ERECTION OF WALLS AND IN THE
CONSTRUCTION OF ARCHES;" in which said Letters Patent there is contained
a proviso, obliging me, the said Edmund Cartwright, 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 one calendar month next imme-
diately after the date of the said recited Letters Patent, 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
Edmund Cartwright, do hereby declare that my Invention consists in giving
bricks, stones, or any other building materials, which may be substituted for those

page_text: articles, such a shape or form as that (when in work) they shall mutually
lock into or cramp each other. The principle of this Invention will readily be
comprehended and understood, by supposing the two opposite side of a common
brick to have a groove or rabbet down the middle, which groove or rabbet
must be a little more than half the width of the side of the brick in which it is
made; there will then be left a shoulder on each side of the
groove or rabbet,
each of which shoulders will be nearly equal to one quarter of the width of the
side of the brick, or to one half of the groove or rabbet, see Figure 1. A
course of these bricks being laid shoulder to shoulder, as in Figure 5, they
will form an indented line of nearly equal divisions, the grooves or rabbets being
somewhat wider than the two adjoining shoulders to allow for mortar, &c.;
when the next course comes on, the shoulders of the bricks which compose it,
will fall into the grooves or rabbets of the first course, and to the shoulders
of the first course will fit into the grooves or rabbets of the second, and so on.
See Figures 1 and 5. This mode of shaping the bricks, &c., as being perfectly
simple, prefer; the principle, however, will be preserved, in whatever manner
they may be made to lock into or cramp each other, by whatsoever form of
indenture, or whether by one groove or rabbet or more. But it must be
observed, in whatever manner the variations from the simple form Figure 1 is
made, except by straight lines, the two sides of the brick, &c., must propor-
tionably vary, so that when they come together in work, they may correspond
and fit each other; an example of which is exhibited in Figure 2, where A
and B show the opposite sides of brick. It may make some small 'saving
in the expence, though, perhaps, not a prudent one, if the bricks, &c., were of
such a width as to admit a common brick or piece of plain stone, &c., between
the shoulders of each of these bricks, &c. In that case, the groove of rabbet
must be made proportionably wider; for the purpose of turning the angles, it
may, be expedient to have bricks or stones of such size and shape as to
correspond with each wall respectively; this, however, is not absolutely
necessary, as the groove or rabbet in the bricks,. &c., of each wall;; where they
cross or meet each other, may be levelled, and the bricks, &c. Imp over as in
the common mode. For the purpose of breaking the joints in the depth of the
walls, bricks, &c. will be required of different lengths; tho of the same width:
Buildings constructed with bricks, &c. of this principle, will require 'no Bond
timber; one universal bond running through and connecting the whole build
ing together, the walls of which can neither crack nor bulge out without
breaking through the bricks, &c. themselves. When these bricks, &c., that
is to
say,
of the simple form Figure 1, are used for the construction of arches.
the sides of the grooves or rabbets and the shoulders should be radii of the
-

page_text: :
circle, of which the intended arch is to be a segment. See Figure 3. Though
if the circle be very large, the difference of the width of the bricks; &c., at
top and bottom, will be so 'triffing as to make a minute attention to this
particular scarcely, if at all, necessary. When 'these arches are required to be
particularly flat, or aro applied in such situations astadmit "not of end walls, as
in the construction of bridges, &c., it may be expedient to have the shoulders
dovetailed, to prevent the arch cracking: across or giving..way endwise. See
Figure 4. If the bricks, &c. are as wide at the bottom as the top, the manner of
putting them together by:n dovetail is obvious,' when not-so-wide at the bottom
as the top; on one side of the brick, &c., the sides of the shoulders must be
parallel; and on, the other sides of the grooves or rabbets, must be parallel
so that the two sides of the bricks, &c., which fall together, may correspond. See
Figure 4, B, C. In forming an arch, the bricks, &c. must be coursed across
the centre on which the arch is turned, and a groovid side of the bricks, &c.,
must face the workman. See Figure 6. It may be expedient (though not
absolutely necessary) in laying the first two or three courses, at least, to, begin
at the crown and work downwards each way. In.arch. work, the bricks; &c,
may be either laid in mortar, or dry; and the interstices, after, filled up and
wedged by pouring in lime, putty, plaister of paris, grouting, or any other;con-
venient material, at-the-discretion of the workman or builder. It is obvious
that arches upon this principle, having no lateral pressure, can-neithen,expand
at the foot, nor spring at the crown; consequently, they will want, no, abut-
ments, requiring only perpendicular walls to be let into or to rest upon; and
they will want no incumbent weight upon the crown to prevent their springing
up, a circumstance of great importance in many situations in the construction
of bridges. Another advantage, attending this, mode of arching is, that the
centres may be struck immediately; so that the same centre (which in no case
need be many feet wide, whatever may be the breadth of the arch) may be
regularly shifted as the work proceeds. But the greatest and most striking
advantage attending this Invention is the absolute security it affords (and at
a very reasonable rate) against the possibility of fire; for, from the peculiar
properties of this arch requiring no abutments, it may be laid upon or let into
common walls no stronger than what are required for timbers, of which it will
preclude the necessity and save the expence.
i
In witness whereof, I, the said Edmund Cartwright, have hereunto set my
hand and seal, this Twenty-ninth day of April, in the year of our
Lord One thousand seven hundred and minste form

page_text: EXPLANATION OF THE FIGURES REFERRED TO IN THE ABOVE SPECIFICATION.
Figure 1, A, the side of the brick; B; the plan; Figure 2, a brick, in which
the two sides A and B vary, that when they come together in work they may
correspond and fit each other; Figure 3, the side of a brick, the sides of whose
shoulders are radii of a circle; Figure 4, dovetail'd bricks; A; as they appear
in work endwise; B and C, the two sides of the dovetail'd bricks when wider at
the top than bottom; Figure 5 shews the face of an upright wall, and also the
appearance of the bricks, &c., both on the upper and under side of an arch;
Figure 6, an arch as it faces the workman.
Scaled and delivered in the presence of
FRA. THIRKILL.
HLEN. REELER.
AND BE IT REMEMBERED, that on the same Twenty-ninth day of
April, in the year above mentioned, the aforesaid Edmund Cartwright came
before our Lord the King in His Chancery, and acknowledged the Speci-
fication aforesaid, and all and everything therein contained, in form above
written. And also the Specification aforesaid was stamped according to
the tenor of the Statute in that case made and provided.