The Works Of Messrs. Schneider And Co.

148 MESSRS. SCHNEIDER AND CO.’S WORKS. by General Marcille, as being that which met the pur- pose beat. The Marcille bridges are divided in two groups, large and small ; they are essentially portable, and are divided in sections as large as can be conveniently håndled. The small bridges are in two classes : tbose of 10 metres (32 ft. 10 in.) and under, and those of 10 to 20 metres (32 ft. 10 in. to 65 ft. 7 in.). They are made to receive the railway line on the top. The large types are also in two classes : from 20 to 30 metres (65 ft. 7 in. to 98 ft. 5 in.) and from 30 to 45 metres (98 ft. 5 in. to 147 ft. 7 in.). The large bridges are made for top or bottom line indifferently, and in botli cases they can be fitted with a wood flooring for the passing of troops and artillery. The elements of small bridges are in sections of 10, 5, 2.50, and 1.25 metres, and these sections methodically of works that necessitated urgent repairs, and the experi- ments already made tend to show that in time of war their great reputation would be fully justifiée!. The system, which is different from Messrs. Schneider and Co.’s system of floating bridges, is illustrated by Figs. 477 to 483; 484 to 486, Plate XCIV., and by Figs. 487 to 493. Fig. 484 shows in elevation and plan the general arrangement of the plant for spanning the two broken arches. In Fig. 485 the bridge is shown supported on the hauling rollers, by which it is moved over tlie gap, and takes its bearings as in Fig. 486. The method of forming the bearings is illus- trated in Figs. 487 to 493, as well as the means provided for lowering the ends upon the bedplates. Military Bridges — Colonel Pfund’s System for Field Service (Figs. 494 to 502).—-These bridges are designed for locations difficult to approach, and they can be used for railway lines and the passing of heavy Fig .493 The Marcille System of Military Bridges. combinée!, form bridges, the length of which is on an arithmetical progression with the ratio of 1.25 metres. Those of the large bridges are in sections of 10, 7.50, 2.50, and 1.666 metres, which, when combinée), form bridges the length of which is on an arithmetical progression with a ratio of 0.83 metre. Mild steel is used throughout, with a breaking strain of 45 kilogrammes (28.57 tons per square inch) and 20 per cent, élongation. When erected, these bridges only weigh, per running metre, 550, 785, 1,500, and 2,200 kilogrammes for spåns of 10, 20, 30, and 45 metres. The time required for érection on the spot is as follows : c f 10 20 30 45 metres. Bridges of I g 12 46 g0 houra The varions elements are stored in dépôt in such a way as to form complété sections of line ; ail the sections can be put on trucks, and can pass under the French railway wagon gauges. Loading and unloading are efiected with great rapidity, with the help of shears forming part of the material. These bridges have already rendered great service in time of peace, for the rapid replacing trucks. Expérience has shown that not more than 60 per cent, of the traffic required in war time will be over heavy bridges, the remaining 40 per cent, being over lighter bridges laid down on emergency. Colonel Pfund, of the Swiss Corps of Engineers, is the inventor of this very rapid and ingenious method of erecting’ bridges, based on the forward motion of wheels ; the spokes of which would be of varions lengths, corres- ponding to the varions cleptlis of the river or other obstacle to be crossed. With this view the “ axles ” that serve to hold the superstructure carry at each end a socket in which pass two movable pointed piles, that can be made fast at any height by means of a screw or a pin. a. Infantry Bridges.—Each bridge consista of the superstructure, the bridge-forming device, and an Inter- mediate support ; each bay is 7 metres (23 ft.) spån from centre to centre of the double X_piles an<^ 1.200 metre (3 ft. 11 in.) wide, this width being sufficient for the Cross- ing of troops two abreast, and of horses in single file. The intermediate support (which is similar to the bridge-form-