Passage of military bridges.
1. Great attention and caution are required in passing over pontoon bridges, the vibratory motion of which is very dangerous, and should be lessened by every possible means.
2. The troops, in passing, should not preserve an equal pace. There should be no halt on the bridge. As soon as the bridge is perceived to rock, the passage of the troops must be stopped.
3. The greatest precaution is necessary to prevent accidents in tide rivers at low water. Unless battens are nailed across the chesses on the slopes, the horses will have the greatest difficulty in keeping their feet, indeed if the chesses be wet it will be impossible; the men must therefore always assist; holding on when going down, and manning the wheels when going up.
4. The drivers must in some cases dismount, and an interval must be left between the carriages equal to their own length; they must be passed over gently. In wet weather over chesses, great care must be taken to prevent the horses slipping. It may sometimes be necessary, unless the bridge be strong, to pass the carriages and horses over separately.
5. In passing over a flying bridge, it may occasionally be advisable to take the horses out; and in boisterous weather, or at night, the wheels should be locked.
Crossing a bridge, and passing a defile.
1. The battery should always pass with the largest front possible.
2. The artillery must be previously posted to the right and left of the bridge; if it be flat, and that the other side can be seen, a gun or two should be placed on each side, and close to the road leading to it; these guns should cross first and come into action on the other side, the remaining guns continue in action and follow by degrees; they should be posted at such a distance from the bridge, that they may keep up a fire while the others are crossing and forming.