possible by troops sent over in boats for the purpose of dislodging
the enemy who might interfere with the progress of the work; and
these troops should take possession at once of any villages, woods,
or other obstacles in the vicinity.

3. It is of importance also to arrange large batteries of heavy
caliber, not only to sweep the opposite bank, but to silence any
artillery the enemy might bring up to batter the bridge while
building. For this purpose it is convenient to have the bank from
which the passage is made somewhat higher than the other.

4. The proximity of a large island near the enemy's bank gives
great facilities for passing over troops in boats and for
constructing the bridge. In like manner, a smaller stream emptying
into the larger near the point of passage is a favorable place for
collecting and concealing boats and materials for the bridge.

5. It is well to choose a position where the river makes a
re-entering bend, as the batteries on the assailant's side can
cross their fire in front of the point where the troops are to land
from the boats and where the end of the bridge is to rest, thus
taking the enemy in front and flank when he attempts to oppose the
passage.

6. The locality selected should be near good roads on both banks,
that the army may have good communications to the front and rear on
both banks of the river. For this reason, those points where the
banks are high and steep should be usually avoided.

The rules for preventing a passage follow as a matter of course from