uld rejoin the column and their proper
subdivision as soon as practicable. When the advance party is strong
enough, the patrols should be sent out from it. When depleted by the
patrols sent out, the advance party should be reenforced during a halt
by men sent forward from the support. If it be impracticable to send
patrols from the advance party, they will be sent from the support.

Where the country is generally open to view, but localities in it
might conceal an enemy of some size, reconnaissance is necessary.
Where the road is exposed to fire and the view is restricted, a patrol
should be sent to examine the country in the direction from which
danger threatens. The object may be accomplished by sending patrols to
observe from prominent points. When the ground permits and the
necessity exists, patrols may be sent to march abreast of the column
at distances which permit them to see important features not visible
from the road.

Mounted scouts or cavalry, when available, should be used for flank
patrols.

651. Cases may arise where the best means of covering the head and
flanks of the column will be by a line of skirmishers extending for
several hundred yards to both sides of the road, and deployed at
intervals of from 10 to 50 yards. A column may thus protect itself
when passing through country covered with high corn or similar
vegetation. In such case, the vegetation forms a natural protection
from rifle fire beyond very short ranges.

652. Fixed rules for the strength, formation, or conduct of advance
guards can not be given. Each case must be treated to meet conditions
as they exist. That solution is generally the best which, with the
fewest men and unbroken units, amply protects the column and
facilitates the advance.

_Rear Guards._

653. A _rear guard_ is a detachment detailed to protect the main body
from attack in rear. In a retreat, it checks pursuit and enables the
main body to increase the distance between it and the enemy and to
re-form if disorganized.

The general formation is that of an advance guard reversed.

654. Its commander should take advantage of every favorable
opportunity to delay the pursuers by obstructing the road or by taking
up specially favorable positions from which to force the enemy to
deploy. In this latter case care must be taken not to become so
closely engaged as to render withdrawal unnecessarily difficult. The
position taken should be selected with reference to ease