By a detachment is meant a body of men sent to act separately from the main army on some particular ser vice. It may consist of infantry or cavalry, or of both ; sometimes it is composed of light troops only ; but in general some of these are combined with the others. The number of men comprehended under the name of a detachment cannot be accurately determined ; but when several battalions and squadrons are combined, they are called a detached corps.
The object for which a detachment is sent out must determine the description of troops to be employed, as well as the conduct which the leader has to pursue. The reasons for sending out detachments may be re duced to the following : I. To carry a reinforcement to some particular quarter. 2. To occupy a post which is necessary for the security of the army, or to keep up the communication. 3. To execute some enterprise against the enemy. 4. To procure information by means of prisoners, or otherwise, and to reconnoitre.
The description of troops to be employed on a de tached service must be determined by the nature of the ground, and by the object to be accomplished. If a post, such as a village, a bridge, an entrenchment, &c. is to be attacked or occupied, the detachment should consist of infantry. If rapidity be the chief requisite, it should consist of cavalry. When the situation and the object seem to require a different kind of troops, dragoons, who can serve on horseback or on foot, may be employed with advantage.
The general rules for every detachment are : 1. To obtain correct information relative to the views of the enemy, in order to provide for our own safety. 2. To form an advanced guard, in proportion to the strength of the detachment, for the purpose of reconnoitring in front. For this service, as well as that of flank pa trolcs, light troops are especially useful. The nature of the ground must determine to what distance this ad vanced guard should proceed, but at all events it must not run the risk of being cut off. 3. Such objects as woods, villages, ravines, heights, growing corns, &c. must not be passed, without being certain, from a strict examination, that no party of the enemy is concealed among them. 4. On entering a defile, the whole troop must be drawn together, and not venture in, until all the neighbourhood has been searched, and we are sure of bring able to pass and form, before the enemy can at tack us. 5. In retiring thiough such a defile, the de tachment should leave a party behind to occupy it, which is afterwards drawn off. The duties of such a
post are, to investigate and give notice of every thing that can interest the detachment, and to oppose every attack as long as possible.
I. With regard to the object in view, the special di rections for a detachment which is sent somewhere as a reinforcement arc, 1. To march secretly, if necessary, requires a very accurate knowledge of the coun try, in order that the troops may proceed under cover of woods, or other objects. The patroles, too, should be instructed to observe the enemy without being them selves seen. 2. Should the detachment fall in with the enemy, it should, whether stronger or weaker, employ all kinds of skilful manoeuvres, and even artifices and stratagems, in order to avoid fighting. 3. If it be im possible to avoid fighting, the detachment must endea vour, by a skilful, prompt, and determined attack, to beat even a superior enemy. 4. The following reasons only can justify a commander in retiring or abandoning his object : An order to do so, on the occurrence of certain circumstances; the obvious impossibility of a successful result, in consequence of the superiority of the enemy ; or if the object could no longer be accomplish ed, even after a successful attack on the enemy. 5. Should the attack succeed, and the enemy be put to flight, the detachment should not think of a keen pursuit, but should immediately proceed to the accomplishment of its ob ject.
II. A detachment intended for the security of the army, or to occupy a post with the view of keeping up the communication, must observe the rules above given on its march, and also the following, when it has arrived at its destination. 1. It must secure itself by entrench ments, according to circumstances, against every attack. 2. It must place its out-posts so as that none of the ene my may pass unperceived along any part of the district which it is intended to cover. 3. When the out-posts are insufficient, this object must be effected by means of patroles. 4. The small detachments of the enemy which would interrupt the communication must be dis persed ; the larger ones must, if possible, be opposed and the advance of a much superior enemy should im mediately be notified at the proper quarter, the retreat made on orders received, or the post defended until reinforcements arrive.