country is such as to make direct communication difficult, connecting
files march between the subdivisions to keep up communication. Each
element of the column sends the necessary connecting files to its
front.

646. A battalion acting as an advance guard should be formed about as
follows: The _reserve_, two companies; the _support_, two companies;
the _advance party_, three to eight squads (about a half company),
depending upon the strength of the companies and the reconnaissance to
be made; the _point_, a noncommissioned officer and three or four men.
Or the reserve may be omitted. In such case the advance party will
consist of one company preceded by a strong point. The remaining
companies form the support.

647. The distances separating the parts of an advance guard vary
according to the mission of the whole force, the size of the advance
guard, the proximity and character of the enemy, the nature of the
country, etc. They increase as the strength of the main body
increases; they are less when operating in rolling, broken country
than in open country; when in pursuit of a defeated enemy than against
an aggressive foe; when operating against cavalry than when against
infantry.

If there be a mounted point, it should precede the dismounted point by
250 to 600 yards. The advance party may be stronger when there is a
mounted point in front. The infantry maintains its gait without
reference to the mounted point, the latter regulating its march on the
former, (_C.I.D.R., No. 2._)

648. To afford protection to an infantry column, the country must be
observed on each side of the road as far as the terrain affords
positions for effective rifle fire upon the column. If the country
that it is necessary to observe be open to view from the road,
_reconnaissance_ is not necessary.

649. The advance guard is responsible for the necessary reconnaissance
of the country on both sides of the line of march.

Special reconnaissance may be directed by the commander of the troops,
or cavalry may be reconnoitering at considerable distances to the
front and flanks, but this does not relieve the advance guard from the
duty of local reconnaissance.

650. This reconnaissance is effected by patrols sent out by the
leading subdivisions of the advance guard. In a large advance guard
the support commander orders the necessary reconnaissance.

Patrols should be sent to the flanks when necessary to reconnoiter a
specified locality and sho