Surprises were much more common in ancient than in modern times, for the noise of musketry and the roar of artillery, belonging to the posts or wings assailed, will prevent any general surprise of an army. Moreover, the division into separate masses, or corps d'armée, will necessarily confine the surprise to a part, at most, of the forces employed. Nevertheless, in the change given to military terms, a surprise may now mean only an unexpected combination of manœuvres for an attack, rather than an actual falling upon troops unguarded or asleep. In this sense Marengo, Lutzen, Eylau, &c. are numbered with surprises. Benningsen's attack on Murat at Zarantin in 1812 was a true surprise, resulting from the gross negligence and carelessness of the king of Naples.

An order of battle is the particular disposition given to the troops for a determined manœuvre on the field of battle. A line of battle is the general name applied to troops drawn up in their usual order of exercise, without any determined manœuvre; it may apply to defensive positions, or to offensive operations, where no definitive object has been decided on. Military writers lay down twelve orders of battle, viz.: 1st. The simple parallel order; 2d. The parallel order with a crotchet; 3d. The parallel order reinforced on one or both wings; 4th. The parallel order reinforced on the centre; 5th. The simple oblique order; 6th. The oblique order reinforced on the assailing wing; 7th. The perpendicular order on one or both wings; 8th. The concave order; 9th. The convex order; 10th. The order by echelon on one or both wings; 11th. The order by echelon on the centre; 12th. The combined orders of attack on the centre and one wing at the same time.

([Figure 14.])[[10]] The simple parallel order is the worst possible disposition for a battle, for the two parties here fight with equal chances, and the combat must continue till accident, superior numbers, or mere physical strength decides the day; skill can have little or no influence in such a contest.

[10]

In the plans, B is the army in position, and A the attacking force arranged according to the different orders of battle. To simplify the drawings, a single line represents the position of an army, whereas, in practice, troops are usually drawn up in three lines. Each figure represents a grand division of twelve battalions.

([Figure 15.]) The parallel order with a crotchet on the flank, is sometimes used in a defensive position, and also in the offensive with the crotchet thrown forward. Malplaquet, Nordlingen, Prague, and Kolin, are examples of this order. Wellington, at Waterloo, formed the parallel order with the retired crotchet on the right flank.

([Figure 16.]) A line of battle parallel to the enemy's, if strongly reinforced on one point, is according to correct principles, and may in certain cases secure the victory; but it has many inconveniences. The weak part of the line being too near the enemy, may, notwithstanding its efforts to the contrary, become engaged, and run the risk of a defeat, and thereby counterbalance the advantages gained by the strong point. Moreover, the reinforced part of the line will not be able to profit by its success by taking the enemy's line in flank and rear, without endangering its connection with the rest of the line.

([Figure 17]) represents the parallel order reinforced on the centre. The same remarks are applicable to this as to the preceding.

These two orders were frequently used by the ancients: as at the battle of Zama, for example; and sometimes by modern generals. Turenne employed one of them at Ensheim.