to cover a siege, protect a capital, guard depots of
provisions and military stores, or some important strategic point. The
general relations of positions with strategy and engineering have
already been considered; we will now discuss merely their relations to
battles.

The first condition to be satisfied by a tactical position is, that its
debouches shall be more favorable for falling on the enemy when he has
approached to the desired point, than those which the enemy can have for
attacking our line of battle. 2d. The artillery should have its full
effect upon all the avenues of approach. 3d. We should have good ground
for manoeuvring our own troops unseen, if possible, by the enemy. 4th.
We should have a full view of the enemy's manoeuvres as he advances to
the attack. 5th. We should have the flanks of our line well protected by
natural or artificial obstacles. 6th. We should have some means of
effecting a retreat without exposing our army to destruction.

It is very seldom that all these conditions can be satisfied at the same
time; and sometimes the very means of satisfying one, may be in direct
violation of another. A river, a forest, or a mountain, which secures a
flank of a line of battle, may become an obstacle to a retreat, should
the defensive forces be thrown back upon that wing. Again, the position
may be difficult of attack in front or on the wings, and at the same
time unfavorable for retreat. Such was Wellington's position at
Waterloo. The park of Hougomont, the hamlet of Haye Sainte, and the
marshy rivulet of Papelotte, were serious obstacles against the
attacking force; but the marshy forest of Soignies in rear, with but a
single road, cut off all hope of retreat.

II. According to the strategic relations of the contending forces in a
campaign, will it be determined whether we are to await the enemy, or to
seek him out and attack him wherever he may be found. We may sometimes
be obliged to make the attack at all hazards, for the purpose of
preventing the junction of two corps, or to cut off forces that may be
separated from the main body by a river, &c. As a general rule the
attacking force has a moral superiority over the defensive, but this
advantage is frequently more than counterbalanced by other conditions.

The main thing in an _offensive_ battle is to seize upon the decisive
point of the field. This point is determined by the configuration of the
ground, the position of the contending forces,