(Figure 19) is the oblique order, with the attacking wing reinforced. This last is better suited for an inferior army in attacking a superior, for it enables it to carry the mass of its force on a single point of the enemy's line, while the weak wing is not only out of reach of immediate attack, but also holds the remainder of the enemy's line in check by acting as a reserve ready to be concentrated on the favorable point as occasion may require. The most distinguished examples under this order are the battles of Leuctra and Mantinea, under the celebrated Epaminondas; Leuthen, under Frederick; the Pyramids, Marengo, and Jena, under Napoleon. (Figure 20.) An army may be perpendicular upon a flank at the beginning of a battle, as was the army of Frederick at Rosbach, and the Russian army at Kunersdorff; but this order must soon change to the oblique. An attack upon both wings can only be made when the attacking force is vastly superior. At Eylau, Napoleon made a perpendicular attack on one wing at the same time that he sought to pierce the enemy's centre. (Figure 21.) The concave order may be used with advantage in certain cases, and in particular localities. Hannibal employed it at the battle of Cannae, the English at Crecy and Agincourt, and the Austrians at Essling, in 1809. (Figure 22.) The convex order is sometimes formed to cover a defile, to attack a concave line, or to oppose an attack before or after the passage of a river. The Romans formed this order at the battle of Cosilinum; the French at Ramilies in 1706, at Fleurus in 1794, at Essling in 1809, and at the second and third days of Leipsic in 1813, and at Brienne in 1814. (Figure 23.) The order by echelon on one wing may be frequently employed with advantage; but if the echelon be made on both wings, there is the same objection to its use as to the perpendicular order on both wings. At Dresden, Napoleon attacked both wings at the same time; this is the only instance in his whole history of a similar attack, and this was owing to peculiar circumstances in the ground and in the position of his troops. (Figure 24.) The echelon order on the centre alone may be employed with success against an army formed in a thin or too extended line of battle, for it would be pretty certain to penetrate and break the line. The echelon order possesses in general very great advantages. The several corps composing the army may manoeuvre separately, and consequently with greater ease. Each echelon covers the flank of that which precedes it; and all may be combined towards a single object, and extended with the necessary _ensemble_. At the battle of the Pyramids, Napoleon formed the oblique order in echelon by squares. Portions of his forces were arranged in echelon in some of his other battles.