IMPROVEMENTS ON GIRDERS FOR BRIDGES AND OTHER STRUCTURES
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
GARDNER, of Wokingham, in the County of Berks, Civil Engineer, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by
Her Royal Letters Patent under the Great Seal of the United Kingdom
of Great Britain and Ireland, bearing date at Westminster, the Ninth
day of December, One thousand eight hundred and forty-eight, in the
twelfth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Gardner, my exors, admors, and assigns,
Her especial licence, full power, sole privilege and authority, that I, the
said John Gardner, my exors, admors, and assigns, or such others as I,
the said John Gardner, my exors, admors, or assigns, should at any time
agree with, and no others, from time to time and at all times 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 "IMPROVEMENTS ON GIRDERS FOR BRIDGES AND OTHER
STRUCTURES;" in which said Letters Patent is contained a proviso, that I,
the said John Gardner, shall cause a particular description of 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, to be inrolled in Her
said Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said in part recited Letters Patent,

page_text: as in and by the same, reference being thereunto had, will more fully and at
large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Gardner, hereby declare that by the term "girders," mentioned in the
title of my said Invention, I mean all beams, bars, or bearings employed in
engineering, building, and architectural structures where materials of great
tensile and compressive force are required, as in bridges, viaducts, aqueducts,
dock gates, railways, archways, roofings, and floorings; and that the said
Invention consists in making or manufacturing the same of cast iron, with a
strengthening or additional bar or bars of wrought iron embodied or dove-
tailed into the same. And I declare that the manner in which the said Inven-
tion is performed is as follows, reference being had to the Drawings hereunto
annexed, that is to say :-
Figure 1 is an elevation of the central part, and one of the ends of a com-
pound girder of this description; Figure 2 is a plan of the same; Figure 3, a
transverse section through the middle (A, B,) of Figure 1; and Figure 4,
another section on the line C, D. A is the girder, which is constructed
mainly of cast iron, and supposed to be suitable to a span of forty feet in
length; B, B, B, are the bottom flanges; C, C, are two wrought-iron bars, which
are introduced into the bottom of the girder at a little distance apart, and are
at the centro of each flange slightly bevilled outwards on each side, so as to be
in those parts dovetailed, as it were, into the girder. The wrought-iron bars
are introduced in the process of casting the girder, such wrought-iron bars
having been previously rolled out into the required sectional form, and well
cleaned of oxide by heating them in a furnace or otherwise.
A modification of the preceding plan is shewn in the sectional view of a
girder given in Figure 5, where there is but one bar of wrought iron used, which
forms the entire bottom of the girder, and is connected to the upper part by a
central ridge of a dovetail form in its cross section, and of an undulating shape
in the longitudinal direction.
Various other modifications in the form of the wrought-iron bars may
suggest themselves and may be adopted without prejudice to the principle of
my Invention.
Figures 6 and 7 shew how this compound mode of construction may be
adapted to railway bars and bearings where these are (as is now ordinarily the
case) of great weight. C, C, are the cast-iron parts, and W, W, the wrought-
iron parts.
And having now described the nature of my said Invention, and in what

page_text: manner the same is to be performed, I declare that what I claim as of my
Invention is, the making of girders for bridges and other structures (using the
girders" in the sense before explained) of cast iron and wrought iron
combined together in the manner before described.
In witness whereof, I, the said John Gardner, have hereunto set my
hand and seal, this Ninth day of June, in the year of our Lord One
thousand eight hundred and forty-nine
Enrolled the Ninth day of June, in the year of our Lord One thousand
eight hundred and forty-nine.