In an attack by surprise, the troops should consist of a storming party and a reserve of picked men. The attacking column is preceded by a company of sappers armed with axes, shovels, picks, crowbars, &c.; bags of powder are also used for blowing down gates, palisades, &c. All the operations must be carried on with the utmost dispatch. The time most favorable for a surprise is an hour or two before day, as at this moment the sentinels are generally less vigilant, and the garrison in a profound sleep; moreover, the subsequent operations, after the first surprise, will be facilitated by the approach of day. Under certain circumstances, it may be advisable to make false attacks at the same time with the true one, in order to distract the attention of the garrison from the true point of danger. But false attacks have, in general, the objection of dividing the forces of the assailants as well as of the assailed. In all attacks by surprise, secrecy is the soul of the enterprise. In an open assault, if artillery be employed, the troops should be drawn up in a sheltered position, until the fire of the works is silenced, and breaches effected in the parapet. But if the bayonet alone be resorted to, the troops are immediately brought forward at the beginning of the assault. The attack is begun by a storming party of picked men: they are preceded, as before, by a body of sappers, provided with necessary means for removing obstacles, and followed by a second detachment of engineers, who will widen the passages, and render them more accessible to the main body of troops who now advance to the assistance of the storming party. If the assailants should be arrested at the counterscarp by obstacles which must be removed before any farther progress can be made, the infantry troops of the detachment display and open a fire upon the assailed, in order to divert their fire from the sappers. A few pieces of light artillery, on the flanks of the column, may sometimes be employed for this purpose with great advantage. The storming party should always be provided with scaling-ladders, planks, fascines, &c., for crossing the ditch, and mounting the scarp. If the counterscarp be revetted with masonry, the troops must either descend by ladders, or fill up the ditch with fascines, bales of straw, bundles of wool, &c.: if not revetted, a passage for the troops into the ditch will soon be formed by the shovels of the sappers. When the ditch is gained, shelter is sought in a dead angle till the means are prepared for mounting the scarp, and storming the work. If the scarp be of earth only, the sappers will soon prepare a passage for the escalade; but if revetted with masonry, the walls must be breached with hollow shot, or scaled by means of ladders.