successive points of the front.

An army should never long occupy any strategic point without making
selection of one or two tactical positions, for the purpose of there
concentrating all the disposable force, and giving battle to the enemy
when he shall have unveiled his designs. In this manner Napoleon
prepared the fields of Rivoli and Austerlitz, Wellington that of
Waterloo, and the Archduke Charles that of Wagram.

When an army either camps or goes into quarters, the general should be
careful that the front be not too extended. A disposition which might be
called the strategic square seems best, presenting three nearly-equal
faces, so that the distance to be passed over would be about equal for
all the divisions in concentrating upon the common center to receive an
attack.

Every strategic line of defense should always possess a tactical point
upon which to rally for defense should the enemy cross the strategic
front. For instance, an army guarding a bank of a river, not being able
to occupy in force the whole line, ought always to have a position in
rear of the center selected, upon which to collect all his divisions, so
as to oppose them united to the enemy when he has succeeded in effecting
a passage.

For an army entering a country with the purpose either of subjugation
or of temporary occupation, it would always be prudent, however
brilliant may have been its earlier successes, to prepare a line of
defense as a refuge in case of reverse. This remark is made to complete
the subject: the lines themselves are intimately connected with
temporary bases, and will be discussed in a future article, (XXIII.)

FOOTNOTES:

[Footnote 9: This does not refer to intrenched camps, which make a great
difference. They are treated of in Article XXVII.]

[Footnote 10: It is a question here of positions of camps, and not of
positions for battle. The latter will be treated of in the chapter
devoted to Grand Tactics, (Article XXX.)]

ARTICLE XXI.

Zones and Lines of Operations.

A zone of operations is a certain fraction of the whole theater of war,
which may be traversed by an army in the attainment of its object,
whether it act singly or in concert with other and secondary armies. For
example, in the plan of campaign of 1796, Italy was the zone of the
right, Bavaria that of the center, Franconia that of the left army.

A zone of operations may sometimes present but a single _line of
operations_, either on acc