Elements of Military Art and Science / Or, Course Of Instruction In Strategy, Fortification, Tactics Of Battles, &C.; Embracing The Duties Of Staff, Infantry, Cavalry, Artillery, And Engineers; Adapted To The Use Of Volunteers And Militia; Third Edition; With Critical Notes On The Mexican And Crimean Wars.

by H. W. Halleck

We will now discuss the employment of the combined arms on the field of battle.

Before the French Revolution, all the infantry, formed by regiments and brigades, was united in a single body and drawn up in two lines. The cavalry was placed on the two flanks, and the artillery distributed along the entire line. In moving by wings, they formed four columns, two of cavalry and two of infantry: in moving by a flank, they formed only two very long columns; the cavalry, however, sometimes formed a third and separate column in flank movements, but this disposition was rarely made.

The French Revolution introduced the system of grand divisions composed of the four arms combined; each division moved separately and independently of the other. In the wars of the Empire, Napoleon united two or more of these divisions into a corps d'armée, which formed a wing, the centre, or reserve of his grand army. In addition to these divisions and corps d'armée, he had large reserves of cavalry and artillery, which were employed as distinct and separate arms.

If the forces be sufficiently numerous to fight by corps d'armée, each corps should have its own reserve, independent of the general reserve of the army. Again, if the forces be so small as to act by grand divisions only, each division should then have its separate reserve.

An army, whether composed of separate corps or of grand divisions, usually forms, on the field of battle, a centre, two wings, and a reserve. Each corps or division acts by itself, with its infantry, cavalry, artillery, and engineer troops. The reserve of cavalry may be formed in rear of the centre or one of the wings. In small forces of fifty or sixty thousand men, the cavalry may act with advantage on the wings, in the manner of the ancients. If the reserve of this arm be large enough to form three separate bodies, it may itself very properly be formed into a centre and wings. If it be formed into two columns only, they may be placed in rear of the openings between the centre and the wings of the main force. The reserve of artillery is employed either to reinforce the centre or a wing, and in the defensive is frequently distributed throughout the whole line of battle. In offensive operations, it may be well to concentrate as much fire as possible on the intended point of attack. The mounted artillery either acts in concert with the cavalry, of is used to reinforce that arm; the light-foot acts with the infantry, and the batteries of heavy calibre are distributed along the line, or concentrated on some important point where their fire may be most effectual. They reach the enemy's forces at a distance, and arrest the impulsion of his attack. They may also be employed to draw the fire of his artillery; but their movements are too slow and difficult for a reserve.

The order of succession in which the different arms are engaged in a battle, depends upon the nature of the ground and other accidental circumstances, and cannot be determined by any fixed rules. The following, however, is most frequently employed, and in ordinary cases may be deemed good.

The attack is first opened by a cannonade; light troops are sent forward to annoy the enemy, and, if possible, to pick off his artillerists. The main body then advances in two lines: the first displays itself in line as it arrives nearly within the range of grape-shot; the second line remains in columns of attack formed of battalions by division, at a distance from the first sufficient to be beyond the reach of the enemy's musketry, but near enough to support the first line, or to cover it, if driven back. The artillery, in the mean time, concentrates its fire on some weak point to open a way for the reserve, which rushes into the opening and takes the enemy in flank and rear. The cavalry charges at the opportune moment on the flank of the enemy's columns or penetrates an opening in his line, and cutting to pieces his staggered troops, forces them into retreat, and completes the victory. During this time the whole line of the enemy should be kept occupied, so as to prevent fresh troops from being concentrated on the threatened point.

The following maxims on battles may be studied with advantage:—1st. General battles are not to be fought but under the occurrence of one of the following circumstances: when you are, from any cause, decidedly superior to the enemy; when he is on the point of receiving reinforcements, which will materially effect your relative strength; when, if not beaten or checked, he will deprive you of supplies or reinforcements, necessary to the continuance or success of your operations; and, generally, when the advantage of winning the battle will be greater than the disadvantage of losing it.

2d. Whatever may be your reason for risking a general battle, you ought to regard as indispensable preliminaries,—a thorough knowledge of the ground on which you are to act; an ample supply of ammunition; the most perfect order in your fire-arms; hospital dépôts regularly established, with surgeons, nurses, dressings, &c., sufficient for the accommodation of the wounded; points of rendezvous established and known to the commanders of corps; and an entire possession of the passes in your own rear.

3d. The battle being fought and won, the victory must be followed up with as much alacrity and vigor, as though nothing had been gained,—a maxim very difficult of observance, (from the momentary disobedience which pervades all troops flushed with conquest,) but with which an able general will never dispense. No one knew better the use of this maxim than Napoleon, and no one was a more strict and habitual observer of it.