the enemy is putting forth all his strength in
repelling the attack.

These considerations lead to the belief that if the general and the
troops of the defensive army are equally active in the performance
of their duty, and preserve their presence of mind, if their flanks
and line of retreat are not threatened, the advantage will usually
be on their side at the second collision of the battle; but to
insure that result their second line and the cavalry must be
launched against the victorious battalions of the adversary at the
proper instant; for the loss of a few minutes may be irreparable,
and the second line may be drawn into the confusion of the first.

12. From the preceding facts may be deduced the following truth:
"that the most difficult as well as the most certain of all the
means the assailant may use to gain the victory consists in
strongly supporting the first line with the troops of the second
line, and these with the reserve, and in a proper employment of
masses of cavalry and of batteries, to assist in striking the
decisive blow at the second line of the enemy; for here is
presented the greatest of all the problems of the tactics of
battles."

In this important crisis of battles, theory becomes an uncertain
guide; for it is then unequal to the emergency, and can never
compare in value with a natural talent for war, nor be a sufficient
substitute for that intuitive _coup-d'oeil_ imparted by experience
in battles to a general of tried bravery and coolness.

The simultaneous employment of the largest number of troops of all
arms combined, except a small reserve of each which should be
always held in hand,[27] will, therefore, at the critical moment of
the battle, be the problem which every skillful general will
attempt to solve and to which he should give his whole attention.
This critical moment is usually when the first line of the parties
is broken, and all the efforts of both contestants are put
forth,--on the one side to complete the victory, on the other to
wrest it from the enemy. It is scarcely necessary to say that, to
make this decisive blow more certain and effectual, a simultaneous
attack upon the enemy's flank would be very advantageous.

13. In the defensive the fire of musketry can be much more
effectively u