arge forces, an advance and rear guard performs such
duty for several days, the outpost, during this period, is furnished
by the advance or rear guards.

When the command is small and stationary for several days, the outpost
is relieved daily. In large commands, the outpost will, as a rule, be
relieved at intervals of several days.

682. The positions held by the subdivisions of the outpost should
generally be prepared for defense, but conditions may render this
unnecessary.

Troops on outpost keep concealed as much as is consistent with the
proper performance of their duties; especially do they avoid appearing
on the sky line.

Outpost troops do not render honors.

_Distribution of Outpost Troops._

683. The outpost will generally be divided into three parts. These, in
order from the main body, are the _reserve_, the line of _supports_,
and the line of _outguards_.

The distances separating these parts, and their distance from the main
body, will depend upon the object sought, the nature of the terrain,
and the size of the command. There can be no uniformity in the
distance between supports and reserve, nor between outguards and
supports, even in the same outpost. The avenues of approach and the
important features of the terrain will largely control their exact
positions.

The outpost of a small force should ordinarily hold the enemy beyond
effective rifle range of the main body until the latter can deploy.
For the same purpose the outpost of a large force should hold the
enemy beyond artillery range.

684. The _reserve_ constitutes the main body of the outpost and is
held at some central point from which it can readily _support the
troops in front_ or _hold a rallying position_ on which they may
retire. The reserve may be omitted when the outpost consists of less
than two companies.

The reserve may comprise one-fourth to two-thirds of the strength of
the outpost.

685. The _supports_ constitute a line of _supporting_ and _resisting_
detachments, varying in size from a half company to a battalion. They
furnish the line of _outguards_.

The supports are numbered consecutively from right to left. They are
placed at the more important points on the outpost line, usually in
the line on which resistance is to be made in case of attack.

686. As a general rule, roads exercise the greatest influence on the
location of supports, and a support will generally be placed on or
near a road. The section which i