light equipage, 130 lbs.; foot-bridge, 16 lbs. One "division" (225 ft. of bridge) of the heavy equipage requires 16 wagons to transport it, and covers a road space of about 300 yards. One division (186 ft. of bridge) of the light equipage requires 14 wagons and a road space of about 250 yds. One division (285 ft. of bridge) of the foot-bridge can be transported in one three-ton truck.

Lacking the standard equipage, almost any kind of boats, rafts, casks, or in fact anything that will float, may be utilized as supports for an improvised bridge.

The heavy equipage has the advantages of greater strength and capacity, and less vulnerability to hostile fire. The light (canvas) equipage has the advantage of greater mobility in transport. The heavy train is required when heavy loads are to be carried, when very swift streams are to be crossed, or when the bridge must resist ice and drift, or stand up under hostile fire.

The erection of the ponton bridge takes the form of a drill, and is accomplished in an incredibly short period of time by men who have been properly instructed. The equipage, moreover, is so simple that average soldiers may be quickly trained to install it.

There is no stream too wide, too deep, or too swift for the ponton equipage, when handled by trained men. As an indication of its capacity, adaptability, and speed of erection, the following historical examples will be of interest.

On June 15th, 1864, Gen. Grant, in his attack on Richmond, had need of a crossing of the James River. The stream was deep, and so swift that the pontons could not be held by their own anchors, it being necessary to attach their cables to schooners placed in the stream. The crossing was over 2,000 ft. wide, 101 heavy pontons being employed, and was completed in 52 hours, or at an average speed of 6 ft. per minute.

In February, 1862, a bridge of 60 boats was thrown across the Potomac at Harper's Ferry. The river was in flood—a perfect torrent—carrying great quantities of ice and drift. In spite of all these difficulties, the structure was successfully completed in 8 hours-average speed of erection, 2 1/2 ft. per minute.

In the winter of 1919 a ponton bridge was built across the Chattahoochee River at West Point, Ga., by a detachment of the 7th Engineers with civilian assistants. The bridge was reinforced to carry heavy traffic, and the flooring was spiked in place. It was installed during a flood, the current varying from 5 to 10 miles per hour, and the water level rising 4 ft. during construction. The length was 440 ft.; and the bridge was completed in 10 hours' working time.

These performances under service conditions, remarkable as they be, are quite eclipsed by the exhibition bridge constructed across the Rhine (near Honningen) by the 1st Engineers, American Expeditionary Forces, during the military occupation of Germany (1919).  The river at this