OF THE TVNE AXD NEIGHBOURING DISTRICTS. l->i 



construction of wrought iron gates for docks, and have made 38 wrought 

 iron bridges, amongst which, as most noteworthy, may be mentioned 

 the Kaffie Azzayat Bridge over the River Nile. The total length of this 

 bridge is 1,607 feet. It is composed of four fixed openings, each 114 

 feet wide, and two swing openings, each 80 feet wide. The girders are 

 box shaped, and are carried upon wrought iron cylinders, 10 feet 

 in diameter and about 90 feet long. The gross weight of this bridge, 

 with the supporting cylinders, amounts to 2,634 tons. 



The firm of Gilkes, Wilson and Co., of Middlesbro', have recently 

 executed from the designs of Mr. T. Bouch some lattice bridges for the 

 South Durham and Lancashire Union Railway, of a peculiar light and 

 cheap construction. Of these the Beelah Viaduct may be looked upon as 

 the most interesting specimen of construction and workmanship. It is 

 constructed upon a somewhat similar plan to the celebrated Crumlin Via- 

 duct, from which, however, it differs in many essential points. This Beelah 

 viaduct consists of 6 f teen pieces, composed of hollow columns. "The 

 span of the lattice girders, forming the roadway, is 60 feet in width. 

 The total length is 1,000 feet, and the greatest depth, from the rail to 

 the ground, is 195 feet. The quantity of materials used in construction 

 consists of 776 tons of cast iron, 303 tons of wrought iron, 12,343 cube 

 feet of Memel timber for roadway. 



Sir William G. Armstrong and Co. have been engaged extensively in 

 designing and manufacturing iron bridges. They have constructed 25 

 moveable and 44 fixed bridges. With one or two exceptions, the whole 

 of the former are worked upon the hydraulic system introduced by 

 them. 



The swing and draw bridges at the Birkenhead, Liverpool, and 

 London Docks, and upon the Swansea and Neath and Great Western 

 Railways, are among the most noteworthy of this class. The largest 

 fixed bridge constructed by this firm is the one which crosses the river 

 Somme, in India, made after the plans of Mr. G. Rendel, now one of the 

 partners of this firm. Being about one mile in length, it boasts of being 

 the longest bridge but one in the world. It is formed with 28 spans. 

 The girders, carrying a railway platform above, and a common roadway 

 beneath, are of the lattice construction, the top section being composed 

 of wrought iron boxes, and the lower section of tension bars. The 

 girders are carried upon brick piers. The total weight of this bridge, 

 including the pier superstructures, which are of iron, is about 4,000 

 tons. Sir W. G. Armstrong and Co. have also turned out from their 

 works caissons, dock gates, pontoons, coffer dams, saddle-back barges, 

 wrought iron dredgers, and a variety of works of this description. 

 _ There are many other firms in the district engaged in constructing 

 classes of work similar to those before referred to. Enough, however, 

 has been said to show the important position whicli this district 

 holds in the branch of industry whose history and development have 

 been shortly traced in this paper. 



