A METHOD OF CONSTRUCTING IRON WORK FOR CERTAIN PARTS OF BUILD- INGS
Year: 1811

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
PEARSALL, of Willsbridge, in the Parish of Bitton, in the County of Gloucester,
Iron Manufacturer, 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 Thirtieth day of
October, in the fifty-second year of His reign, give and grant unto me, the
said Thomas Pearsall, my executors, administrators, and assigns, His especial
licence, full power, sole privilege and authority, that I, the said Thomas
Pearsall, 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 Inven-
tion of "A METHOD OF CONSTRUCTING IRON WORK FOR CERTAIN PARTS OF BUILD-
INGS;" in which said Letters Patent there is contained a proviso obliging
me, the said Thomas Pearsall, by an instrument in writing under my hand
and seal, to cause a particular description 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 two calendar months after the date of the said
recited Letters Patent, as in and by the same, relation being thereunto had,
will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Pearsall, do hereby declare that the nature of my said Invention,
and in what manner the same is to be performed, is described as follows
(that is to say):-

page_text: The principle of my Invention consists in the application and fixing of thin
wrought or malleable iron plates in an edgewise position, so as to render them
capable of sustaining a very considerable weight. Roofs are by this means
constructed to receive any kind of covering, by uniting, by means of rivets,
pins, screws, or ties, plates of iron of the necessary thickness and dimensions
for rafters and laths, cut or let one into the other, of a sufficient depth to keep
them perfectly fixed in their required position. The rafters are pinned or other-
wise fastened together at the top, as at (a), Figs. 1, 2, 3, 4, in the margin
hereof, and at this point another plate (6) is fastened, falling perpendicularly,
which meets and is united to two others (c, d), running therefrom on each side
to the rafters, and generally as near the foot of the rafters as possible, or
according as circumstances may require. These two latter plates are pinned
or otherwise fastened to the rafters, and are what I term the stays; these
stays are put on either in a level or diagonal form, or in a curved form, so as
to form an arch. An assemblage of these rafters and stays, connected at
certain distances by the laths, being wedged or otherwise fastened into the
'rafters, with the addition, if required, of some crossings or braces on the under
side of the rafters and on the stays, laid either flat or edgewise, form a roof.
Iron, about three inches and a quarter of an inch wide, and about one eighth
of an inch thick, is found sufficiently strong for rafters, without any support,
otherwise than as before described, to bear with ease the common pantile on a
span of twenty-five feet; the laths and stays of a size in proportion, which
'I find to be about one inch and three quarters of an inch wide, and full one
sixteenth of an inch thick on the extension of the span. Supports are intro-
duced in various forms, according to the extent required.
In the margin of these Presents are shown three sections of roofs of twenty-
five feet span, also one of roofs from twenty-five feet span to forty feet, and
one from forty feet to any further extent the Invention may be applied to, with
the supports required. They are given merely as specimens of the most
eligible mode of constructions, and may be altered according to circumstances.
Figure 1 represents the rafters, with the notches cut in them to receive the
laths, and also the horizontal and perpendicular stays for supporting such a
roof. Fig. 2 shews the diagonal stays, and Fig. 3 the curved stays, with the
addition of a mode of laying and fixing the bearings D, E, for gutters,
constructed on the same principle as the roof.
Fig. 4 shews a method of forming a roof from twenty-five feet to forty feet
span, with a curved support e, g, I, f.
Fig. 5 shows the method of forming a roof from forty feet upwards, supported
"by the arch C, with the chord D, and by the four bearing and pendant stays

page_text: Joists for floors are prepared and laid down by the same method which
unites the rafters and laths; and by the same method also iron is fixed for
ceilings and partitions, though occasionally in this work it may be laid flat.
Skeletons for stairs are made on the same principle, to receive steps, wood or
stone; and on the same principle also are made doors, windows, and skylights,
and other things of a like nature.
In witness whereof, I, the said Thomas Pearsall, have hereunto set my
hand and seal, this Twenty-sixth day of December, in the fifty-second
year of the reign of our Sovereign Lord George the Third, by the
grace of God of the United Kingdom of Great Britain and Ireland
King, Defender of the Faith, and in the year of our Lord One
thousand eight hundred and eleven.