spirit of Napoleon's warfare
would hardly fail to make his enemy's communications his first
objective."---Col. G. F. R. HENDERSON.

The Flanks are the most vulnerable points of an army, for an attack
upon these points subjects the defenders to enfilade fire, and is
delivered by troops arrayed in attack formation against an enemy that
is not in a position to repel the attack. The consequences of a
successful Flank Attack are so far-reaching that every effort will be
made by a commander to bring about such a consummation in order that he
may sever his adversary's communications, bring him to the end of his
resources, and deprive him of the means of replenishing them.

If, therefore, there is any possibility of a column on the march being
attacked in flank a force must be detached to protect that flank, and
if both flanks are exposed to attack both must be similarly protected.
The flank is the most vulnerable part of a moving column, and an attack
driven home upon that part has every prospect of success, for it will
be delivered by a force that is distributed in depth against a force
that is protracted in width after changing front to meet the attack,
and the absence of depth in the defending force will deprive the
defence of the principal source of strength in resisting attack.

An independent column is liable to attack on either of its flanks,
unless the nature of the country through which it is passing provides
security for one or the other in the form of an impenetrable feature
(such as a wide, {115} trackless marsh), or an impassable barrier (such
as a neutral frontier). The outer columns of a force moving on
parallel routes will have an exposed flank, while their inner flank is
protected by maintaining touch with the neighbouring column.

Flank Guards may be furnished by the Main Body, or by the Advanced
Guard, and this point will be made clear in the orders for the
operations. Their composition, strength, and distribution, and the
interval at which they move on the flank of the Main Body, are similar
to those of an Advanced Guard, while their action under all
circumstances is governed by the same tactical considerations, the
principle underlying every action of a Flank Guard commander being
compliance with the known intentions of the commander of the Main Body,
and the sacrifice of the interests of the Flank Guard to preserve the
interests of the Main Body. The same duties of reconnaissance and
protection