By these means a pretty accurate knowledge may be obtained of the natural features of the ground exterior to the works; their weak and strong points; and their interior arrangements for defence.
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.