AN IMPROVEMENT IN THE MANUFACTURE OF CHAINS, WHICH I DENOMINATE MATHEMATICAL CHAINS
Year: 1822

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
SMART, of Pedlars Acre, Lambeth, in the County of Surrey, Civil Engineer,
send greeting.
WHEREAS His most Excellent Majesty King George the Fourth did, by
His Letters Patent under the Great Seal of that part of the United Kingdom
of Great Britain and Ireland called England, bearing date at Westminster,
the Fourth day of July, One thousand eight hundred and twenty-two, in the
third year of His reign, give and grant unto me, the said George Smart, my
exors, adñiors, and assigns, His espicial licence, full power, sole privilege and
authority, that I, the said George Smart, 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, and also in all His Majesty's Colonies and Plantations abroad,
my Invention of "AN IMPROVEMENT IN THE MANUFACTURE OF CHAINS, WHICH I
DENOMINATE MATHEMATICAL CHAINS;" in which said Letters Patent there is
contained a proviso, that if I, the said George Smart, shall not particularly
describe and ascertain the nature of my said Invention, and in what manner
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 six calendar months next and immediately after the date of
the said Letters Patent, that then the said Letters Patent, and all liberties
.

page_text: and advantages whatsoever thereby granted, shall utterly cease, determine, and
become void, 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
George Smart, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, are particularly described and
ascertained in and by the Drawings hereunto annexed, and the following
description thereof (that is to say):-
I, the said George Smart, do hereby declare that the nature of my said
Invention in making mathematical chains to prevent undulations; &c., are as
follows: The chains are composed of bars and bolts, forming a combination of
angles supporting one another, that cannot be much altered from a straight line
by any weight such as bridges are exposed to sustain. My Invention having
no thrust on their abutments require no counteracting force to balance their
weights and the loads that pass over them. Those chains may be carried over
a great span without intermediate piers, and are strong, portable, and simple
in execution, as described under.
A, B, and C, are three bars of wrought iron or other metal, with holes
made in them at distances, so as to form the angles required when connected
dy the bolts D, which are screwed at both ends long enough to receive the
plates
or bars that form the sides of the chains,, with two nuts on each (E, E,)
to keep the bars in their places."
Fig. 1: G, a side view of the chain with a floor at F; B, B, B, B, B, the bars,
forming the bases of, the angle; A, the diagonals; and C, the hanging or perpen-
dicular bars, all connected and held together by the bolts D. As there are only
three bars and, one bolt to be attended to, if there are thousands made to those
patterns when the height of the angles are determined on they require no skilful
workmen to put them up, as every bar and bolt will find their places and cannot
be misplaced, they require no marking, and may be put together in the dark.
Two men can carry the heaviest bar A before it is connected with the others.
If extra strength should be wanting the sides may be continued to any depth
required, and bars or rods, may be placed by the sides of the others, or may be
said flat and firmly fixed on the bolts, D, so as to strengthen the bases. Four
of those chains, about six feet wide each, and kept about the same distance
apart, will form a bridge fit for any purpose; may be metal, wood, or partly
both, and are particularly fit for wharfs, harbours, or piers where foundations
are soft and incapable to sustain the weight of stone, &c.; the floor and joists,
whether iron or wood, to be connected by diagonal braceing, the same as the
sides are, as it requires great power to pull asunder. Timber lengthways,

page_text: temporary bridges of fir or other poles or planks, may be put together on my
plan at small expence, as this Invention secures the extremities of the triangles
and throws the strain in a direct line on the bases of the angles. If diagonals
are adopted as this to pendant bridges it would prevent much undulation and
relieve the piers from vibration.