In the oblique order of battle, it is not necessary that the front should precisely describe an oblique line with respect to the enemy's front ; for it seldom happens that the nature of the ground, and other circumstances, Nvia admit of such a perfectly regular formation. Every disposition, then, may he called oblique, in which we bring a part of our forces to act against the enemy, while the rest of the troops arc kept out of his reach ; every disposition, in short, in which we attack, with su perior numbers, one or more points of the enemy's line, while the rest of our troops are placed beyond the reach of being attacked by him. The advantage of this order of battle consists in this, that, by attacking some part of the enemy 's line with superior numbers, we are enabled to penetrate and overwhelm it, to fall upon his flank and rear, and thus force him to retire from the field.
From the nature of the oblique order, the attack must be directed against one of the enemy's wings. The main object to be attained by its means is to make an impression on the point assailed, to continue to outflank it, and to turn its rear. Torender these results practica ble, it is necessary to reinforce the attacking wing, so as to give it a decided superiority over the enemy ; and to prevent him from reinforcing the point about to be attacked, the assailant must have recourse to every de lusive art to mask his real design, until the onset is ac tually commenced. Then the attack most proceed with vigour and rapidity ; no time must be suffered to elapse which might allow the enemy an opportunity to recol lect himself. The onset must he as furious as it is un expected, and he must be overthrown, even before he has had leisure to fire a shot.
In operating thus with a concentrated effort upon one of the extremities of the enemy's line, measures, as we have already hinted, must. be taken to make this attack practicable, by masking the preparatory movements ; for, without this precaution, it would be in the power of the hostile army to move in a corresponding direc tion with the columns intending to turn its flank, and to continue to present a front to them, or even to turn their own flanks. Hence it is necessary to conceal the march of the columns by the obscurity of the night, the con formation of the ground, or by a false attack upon the enemy's front. The two last methods are to be prefer red, especially if they can be employed both together, because movements by night are more liable to uncer tainty and irregularity than those made by day. In or der to alarm a greater extent of front, it may be prefer able to act with a corps of light troops, distributed in platoons, rather than with a continued line in the shape of an advanced guard. This skirmishing force might, according to circumstances, be augmented to six or eight battalions ; and a point should he indicated to them upon which they are finally to close, and where they will be sustained by cavalry and light artillery. This method has the twofold advantage of perplexing the enemy, in regard to the real importance of the false at tacks, and the number of troops employed in them ; and also of attracting the attention, and keeping io check the greater part of his front, while the columns are march ing to their destination.
The oblique order may be executed either in line, or en echelon. When formed in line, the disposition pre sents an oblique front in a half quarter of conversion, (Plate CCCI,XXXIII. Fig. 39 ) When formed by eche lons, each battalion and squadron is out-flanked 011 the side where the attack is made by the battalion or squa dron next it, to the extent of a certain number of paces, more or less considerable, according to the number of troops of which each column is composed, and the de gree of obliquity required in our disposition. All that part of the army, however, which is destined for the attack, forms a sort of hammer in front, placed in the common order, (Fig. 40.) This disposition by echelons, instead of being formed by battalion and squadron, may be taken by regiment or brigade, and even by more con siderable corps ; these corps being placed by echelons at some distance from each other, so as to he able to support each other mutually when necessary, and to oc cupy the positions which can best prevent their being exposed to an attack, and enable them to deceive the enemy. Of these two modes of forming the oblique order, in line, or by echelons, the first is merely elemen tary and methodical. It may be well to practise it in camps of instruction, in order to make the officers ac quainted with the nature and object of the oblique order. The second mode, which is derived from the first, is more simple, easier in its deployment, more applicable to all sorts of ground, and more susceptible of manoeu vre and action when the disposition is formed. There are various ways of forming these oblique disposi tions, which the reader will find described by Guibert and other tactical writers. Meanwhile, we shall notice another species of the oblique order, in which the army, although not drawn up obliquely in front of the enemy, places itself, either from the nature of the ground, or the skilfulness of its movements, in such a situation as enables it to make an attack upon one or more points, while it is itself out of reach of the enemy upon those parts of its line which it is desirous of refusing. This is the order which is most generally adopted in actual warfare, because it seldom happens that battles are fought on plains absolutely smooth and open, where, con sequently, the dispositions may be made without regard to the nature of the ground, and in the regular obliquity established by principles. We are almost always com pelled to abandon this regularity, in order to avail our selves of the advantageous positions which are presented by the nature of the country, either to favour the illu sion which we wish to practise upon the enemy, or to secure the weak parts of our line. Thus, the order of battle at Lissa, or Lcuthen, may be called an oblique disposition, although certainly the army of the King of Prussia was not drawn up obliquely to the front of the Austrians ; but he attacked with a strong body their left wing, took it in flank and overwhelmed it, while, at the same time, he availed himself of a chain of heights, op. posite to their right and centre, in order to deceive them, to keep them in check, and to place in an excellent de fensive position, the rest of his army, which was weak ened by the reinforcements he drew to his right.