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IRON GIRDER BRIDGES,
PARTICULARLY DESCRIBING THE
BRITANNIA AND CONWAY TUBULAR
With a Sketch of Iron Bridges,
ILLUSTRATIONS OF THE APPLICATION OF MALLEABLE IRON
BY G. DRYSDALE DEMPSEY, C.E.,
Author of the "Practical Railway Engineer," "Rudimentary Treatise on the Drainage
Drainage and Sewage
of Towns and Buildings," &c.
VIRTUE BROTHERS AND CO., 1, AMEN CORNER,
ENGINEERING Works being usually of a public character, naturally excite a general interest throughout the community, the extent of which feeling is commonly commensurate with the novelty, the magnitude, and the utility of the performance. Thus, a railway, a harbour, a lighthouse, a dock, or a bridge, regarded as subservient to public convenience, is watched with public anxiety, and its completion becomes an occasion of public gratulation. Such a work is therefore a peculiarly suitable subject for one of a series of Rudimentary Volumes, dedicated, in their several features of style, size, and price, to the use of a largely-extended circle of readers and students. And it must be admitted by all that the works which form the main subjects of the following pages have claims of nearly unprecedented amount upon our attention, being new, great, and useful in a pre-eminent degree.
The application of wrought iron to the purpose of bridgebuilding truly constitutes a new branch of the art, and is, as already proved, susceptible of modifications of form and construction, far more efficient than those of the cast metal. A perfectly horizontal and rigid roadway or railway, 460 feet in length, and having only 3 feet of depth below it, could not be obtained by any other known arrangement of parts than that herein illustrated; and with these successful examples before us, the task of future designing is facilitated to an incalculable extent. For smaller spans the depth of construction may be still further reduced, as shown in the splendid bridge over the Trent, described in this volume; and for the particulars of which we take the pleasure of expressing our obligation to Messrs. Fairbairn and Sons, who have also