the main body, the line of supports, the line of outguards, the line
of sentries and the advance cavalry, will depend upon circumstances.
There can be no uniformity in the distance between supports and
reserves, nor between outguards and supports, even in the same
outpost. The avenues of approach and the important features of the
ground will largely control the exact positions of the different parts
of the outposts. The basic principle upon which the distances are
based, is: _The distance between any two parts of the outpost must be
great enough to give the one in rear time to deploy and prepare for
action in case of attack, and the distance of the whole outpost from
the main body must, in the case of small commands, be sufficiently
great to hold the enemy beyond effective rifle range until the main
body can deploy, and, in case of large commands, it must be
sufficiently great to hold the enemy beyond effective artillery range
until the main body can deploy._

It is, therefore, evident that the distances will be materially
affected not only by the size of the main body, but also by the nature
of the cover afforded by the ground.

The following is given merely as a very general guide, subject to many
changes:

Distance to next
element in rear.

Advance cavalry 2 to 6 miles
Supports {Sentinels (furnished by outguard) 20 to 40 yds.
(Generally {Outguards (furnished by support) 200 to 500 yds.
two or {Support proper furnishes majority 400 to 800 yds.
more) of patrols.
Reserve (usually omitted in small commands) 1/2 to 2 miles

=1056. Advance Cavalry.= The advance cavalry is that part of the
outpost sent out in front of all foot troops. It generally operates
two to six miles beyond the outpost infantry, reconnoitering far to
the front and flanks in order to guard the camp against surprise by
artillery fire and to give early information of the enemy's movements.

After dusk the bulk of the cavalry usually withdraws to a camp in rear
of the outpost reserve, where it can rest securely after the day's
hard work and the horses can be fresh for the next day. Several
mounted patrols are usually left for the night at junctions or forks
on the principal roads to the front, from one to four miles beyond the
infantry line of observation.

=1057.