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 should rejoin the column and their proper subdivision as soon as practicable. When the advance party is strong enough, the patrols should be sent out from it. When depleted by the patrols sent out, the advance party should be reenforced during a halt by men sent forward from the support. If it be impracticable to send patrols from the advance party, they will be sent from the support.
Where the country is generally open to view, but localities in it might conceal an enemy of some size, reconnaissance is necessary.
Where the road is exposed to fire and the view is restricted, a patrol should be sent to examine the country in the direction from which danger threatens. The object may be accomplished by sending patrols to observe from prominent points. When the ground permits and the necessity exists, patrols may be sent to march abreast of the column at distances which permit them to see important features not visible from the road.
Mounted scouts or cavalry, when available, should be used for flank patrols.
651. Cases may arise where the best means of covering the head and flanks of the column will be by a line of skirmishers extending for several hundred yards to both sides of the road, and deployed at intervals of from 10 to 50 yards. A column may thus protect itself when pa.s.sing through country covered with high corn or similar vegetation. In such case, the vegetation forms a natural protection from rifle fire beyond very short ranges.
652. Fixed rules for the strength, formation, or conduct of advance guards can not be given. Each case must be treated to meet conditions as they exist. That solution is generally the best which, with the fewest men and unbroken units, amply protects the column and facilitates the advance.
_Rear Guards._
653. A _rear guard_ is a detachment detailed to protect the main body from attack in rear. In a retreat, it checks pursuit and enables the main body to increase the distance between it and the enemy and to re-form if disorganized.
The general formation is that of an advance guard reversed.
654. Its commander should take advantage of every favorable opportunity to delay the pursuers by obstructing the road or by taking up specially favorable positions from which to force the enemy to deploy. In this latter case care must be taken not to become so closely engaged as to render withdrawal unnecessarily difficult. The position taken should be selected with reference to ease of withdrawal and ability to bring the enemy under fire at long range.
655. In large commands artillery and cavalry form a very important part of the rear guard.
_Flank Guards._
656. A _flank guard_ is a detachment detailed to cover the flank of a column marching past, or across the front of, an enemy. It may be placed in position to protect the pa.s.sage, or it may be so marched as to cover the pa.s.sage.
657. The object of the flank guard is to hold the enemy in check long enough to enable the main body to pa.s.s, or, like the advance guard, to enable the main body to deploy.
Like all other detachments, it should be no larger than is necessary, and should not be detailed except when its protection is required.
658. When a flank guard consists of a regiment or less, its distance from the main body should not exceed a mile and a half. Practicable communication must exist between it and the main body.
659. The flank guard is marched as a separate command; that is, with advance or rear guards or both, as circ.u.mstances demand, and with patrolling on the exposed flank.
660. At times it may be necessary for an advance-guard commander to send out large reconnoitering parties which temporarily a.s.sume the character and duties of a flank guard. Such parties should be given specific orders as to when and where they are to rejoin the column.
CAMPS.
_SANITATION._
661. If the area of the available ground is sufficient and suitable, the camp of the battalion or regiment should conform to the plates published in the Field Service Regulations. Under similar favorable conditions, the brigade may camp in column or in line of columns. In the latter formation the interval between regiments should be about 50 yards. When the camp site has a restricted area, intervals and distances are reduced.
Under service conditions, camp sites that will permit the encampment of regiments and brigades as above indicated will not often be available and regularity must be sacrificed.
662. In large commands the halt order should a.s.sign camp sites to the next smaller commands, and the commanders of the latter should locate their respective commands to the best advantage on the area a.s.signed them.
_The Selection of Camp Sites._
663. In campaign, tactical necessity may leave little choice in the selection of camp sites, but under any conditions the requirements of sanitation should be given every consideration consistent with the tactical situation.
664. Great care should be exercised in selecting sites. In general, the following principles govern:
The site should be convenient to an abundant supply of pure water.
Good roads should lead to the camp. Interior communication throughout the camp should be easy. A camp near a main road is undesirable on account of dust and noise.
Wood, gra.s.s, forage, and supplies should be at hand or easily obtainable.
The ground should accommodate the command without crowding and without compelling the troops of one unit to pa.s.s through the camp of another.
The site should be sufficiently high and rolling to drain off storm water readily, and, if the season be hot, to catch the breeze. In cold weather it should preferably have a southern exposure, with woods to the north to break the cold winds. In warm weather an eastern exposure, with the site moderately shaded by trees, is desirable.
The site should be dry. For this reason porous soil, covered with stout turf and underlaid by a sandy or gravelly subsoil, is best. A site on clay soil, or where the ground water approaches the surface, is damp, cold, and unhealthful.
Alluvial soils, marshy ground, and ground near the base of hills, or near thick woods or dense vegetation, are undesirable as camp sites on account of dampness. Ravines and depressions are likely to be unduly warm and to have insufficient or undesirable air currents.
Proximity to marshes or stagnant water is undesirable on account of the dampness, mosquitoes, and the diseases which the latter transmit.
The high banks of lakes or large streams often make desirable camp sites.
Dry beds of streams should be avoided; they are subject to sudden freshet.
665. The occupation of old camp sites is dangerous, since these are often permeated by elements of disease which persist for considerable periods. Camp sites must be changed promptly when there is evidence of soil pollution or when epidemic disease threatens, but the need for frequent changes on this account may be a reflection on the sanitary administration of the camp.
A change of camp site is often desirable in order to secure a change of surroundings and to abandon areas which have become dusty and cut up.
_Water Supply._
666. Immediately on making camp a guard should be placed over the water supply. If the water be obtained from a stream, places should be designated for drawing water (1) for drinking and cooking, (2) for watering animals, (3) for bathing and washing clothing. The first named should be drawn farthest up the stream; the others, in the order named, downstream.