t is to cover should be clearly
defined by means of tangible lines on the ground and should be such
that the support is centrally located therein.

687. The _outguards_ constitute the line of small detachments farthest
to the front and nearest to the enemy. For convenience they are
classified as _pickets_, _sentry squads_, and _cossack posts_. They
are numbered consecutively from right to left in each support.

688. A _picket_ is a group consisting of two or more squads,
ordinarily not exceeding half a company, posted in the line of
outguards to cover a given sector. It furnishes patrols and one or
more sentinels, double sentinels, sentry squads, or cossack posts for
_observation_.

Pickets are placed at the more important points in the line of
outguards, such as road forks. The strength of each depends upon the
number of small groups required to observe properly its sector.

689. A _sentry squad_ is a squad posted in _observation_ at an
indicated point. It posts a double sentinel in observation, the
remaining men resting near by and furnishing the reliefs of sentinels.
In some cases it may be required to furnish a patrol.

690. A _cossack post_ consists of four men. It is an _observation_
group similar to a sentry squad, but employs a single sentinel.

691. At night, it will sometimes be advisable to place some of the
outguards or their sentinels in a position different from that which
they occupy in the daytime. In such case the ground should be
carefully studied before dark and the change made at dusk. However, a
change in the position of the outguard will be exceptional.

692. _Sentinels_ are generally used singly in daytime, but at night
double sentinels will be required in most cases. Sentinels furnished
by cossack posts or sentry squads are kept near their group. Those
furnished by pickets may be as far as 100 yards away.

Every sentinel should be able to communicate readily with the body to
which he belongs.

693. Sentinel posts are numbered consecutively from right to left in
each outguard. Sentry squads and cossack posts furnished by pickets
are counted as sentinel posts.

694. Instead of using outguards along the entire front of observation,
part of this front may be covered by _patrols_ only. These should be
used to cover such sections of the front as can be crossed by the
enemy only with difficulty and over which he is not likely to attempt
a crossing after dark.

In daylight much of the local