point is 1,450 ft. wide, with a maximum depth of 25 ft. and a current of 3 to 4 miles per hour. The bridge was built from both ends, 400 trained men being employed, and 93 pontons (of the German equipage) being used. The structure was completed in the astonishing time of 41 minutes 8 seconds, or at an average rate of more than thirty-five feet per minute, the world's record for speed in bridge construction.

No other type of bridge ever devised is capable of anything approaching such speed in erection. By contrast with the time required in the cases mentioned, one of the best examples of the construction of a heavy, military trestle-bridge was a structure built over the Little Pedee River in the Civil War, in which a length of 100 ft. was completed in about 9 hours.

The ponton bridge is designed to meet emergencies; and if the crossing is to be required for any considerable period, the ponton equipage should be released by the construction of a fixed bridge, in order that it may be available for fresh emergencies. For the requirements of a moving column in a theatre where stream crossings are encountered, the ponton equipage is indispensable. In addition to its use for bridging, the equipage may also be employed for ferrying, as in the passage of a stream by force in the face of the enemy.

If it be necessary to employ the ponton bridge for a considerable period, the chess (floor plank) should be protected by a sheathing of thin lumber or by hay or brush. These chess are very thin (1 1/2 in.), and, if unprotected, would soon be worn through and ruined by continued traffic.

As just stated, the floating equipage, if available, will often be the first solution for an important emergency crossing. Subsequently, and as soon as possible, it should be replaced by a trestle bridge, which in turn may later be used as falsework for a more elaborate structure.

The adaptability of the ponton equipage is very great; it is ideally fitted to meet military emergencies; and its value as a saver of time cannot be over-estimated.

New Types of Ponton Equipage

The old types of ponton bridge, which have so long served military needs, and which are of generally similar design in all armies, like other former types of military bridges are inadequate to the needs of modern traffic. In future wars a heavier equipage will be required, and even this must be capable of "reinforced" construction to carry the augmented loads. Such an equipage has been designed for the American Army. The pontons have an available buoyancy of 10 tons, the span has been decreased to 15 ft. and heavier balk are used. An all-metal boat, or one of metal sheathing on a wooden frame, will be employed. The adjustable trestles for end spans will be of steel. This bridge will normally carry a concentrated load of 13,500 lbs. on one axle, and may be reinforced to carry an axle load of 20,000 lbs. This will take all the loads of a corps or army, excepting only heavy  tanks  and  the  guns  and  tractors  of  the  artillery  weighing