A picket is a group consisting of one or two sections, ordinarily not exceeding half a company, posted in the line of outposts to cover a given sector. It furnishes patrols and one or more 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.
A sentry squad is a squad (eight men) 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.
A cossack post consists of four men. It is an observation group similar to a sentry squad, but employs a single sentinel.
As a rule not more than one-third of the support should be on outguard duty. As soon as they are sent out to their positions the support commander selects a defensive position on the line of resistance; gives instruction for intrenching same; establishes a sentinel to watch for and transmit signals from outguards; sends out patrols to reconnoiter the country to the front of his section and, if on the flank of the line, the flank; and then proceeds to make a careful reconnoissance of the section assigned him, rectifying the position of outguards if necessary, seeing that they understand their instructions in case of attack or when strangers approach their posts, and pointing out their lines of retreat in case they are compelled to fall back on the support.
When the outguards are established, the members of the support may stack arms and remove equipment except cartridge belts. Part of the horses may be unsaddled and groomed and fed at one time. All girths should be loosened. No fires will be built or smoking permitted unless specially authorized, or no loud talking or other noise. All patrolling to the front will be done, as a rule, from the support. The support commander should locate the position of the adjacent supports and make arrangements with the commanders for the joint defense of the line of resistance. At nights all roads and trails should be carefully covered and the country to the front and between adjacent outguards well patrolled. Horses should, as far as possible, be permitted to rest, unsaddled, at night.
The line occupied by the outguards is called the line of observation. Outguards move to their positions providing for their own protection and so as to conceal the movement from the enemy. These positions are intrenched and are numbered from right to left in each support.
The duties of the outguard are to observe the enemy, to guard the outpost from surprise, and to make a preliminary resistance to the enemy's advance. The strength of the outguard will vary according to its object. When an important road, which at night will afford a line of advance, or a bridge is to be covered, or when several posts are established from an outguard it should be of considerable strength, a section or a platoon. When mere observation and alarm are all that is required four men will suffice. One corporal and seven privates are a good number to use as an outguard; this will allow one double sentry post of three reliefs and one man in addition to the commander, who may be used for messenger service. The outguard should be carefully concealed.
The utmost quiet should be observed, and there should be no cooking or smoking. The intervals between outguards will depend upon the situation and the terrain. The line of observation is not necessarily continuous, but all avenues of approach must be carefully guarded. The distance of the outguard from the support likewise is governed by the terrain, but in general may be said to be from 300 to 400 yards. In thick country or at night outguards patrol along the line of observation between posts. Communication between outguards and the support is by signal and messenger, in special cases by wire. Members of the outguard retain possession of their weapons and do not remove their equipment.
Sentinels from the outguard are posted so as to avoid observation, but so that they may have a clear lookout and be able to see, if possible, by day, the sentinels of the adjacent outguards. Double sentinels are always posted near enough to each other to communicate easily in ordinary voice. Sentinels are generally on post two hours out of six. For every sentinel and every patrol there should be three reliefs, and outguards should be of a strength sufficient to allow this. The position of a sentinel should be selected with reference to observation. It may be advantageous to place a sentinel in a tree. Sentinels furnished by cossack posts or sentry squads are kept near their group. Those furnished by their pickets may be kept as far as 100 yards away.
Reliefs, visiting patrols, and inspecting officers approach sentinels from the rear.