and well managed during the operations of the siege,
they contribute very materially to the length of the defence.

_Attack and defence_.--This subject admits of two natural divisions:
1st, of intrenchments, and 2d, of permanent works.

I. Intrenchments maybe attacked either by _surprise_, or by _open
force_. In either case the operations should be based on exact
information of the strength of the works and the number and character of
the garrison--information that can be obtained from spies, deserters,
and prisoners, and confirmed by examinations or reconnaissances made by
officers of engineers. 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. 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