blinds are arranged to mask the mouths
of the embrasures when the guns are not in battery, and also sloping
blindages to cover the men when serving at the pieces. The possession of
the outworks should be disputed inch by inch, and when the besiegers
have reached the ditch of the body of the place, sorties, and every
species of projectile, should be employed to drive off the sappers, and
to retard the construction of their works. In fine, all the resources of
the engineer's art should be put in requisition for the defence of the
breach, and the final assault should be vigorously resisted by the
bayonet, and by a well-sustained fire from all the collateral works.

With respect to the relative strength of the opposing forces it may be
well to remark, that if the fortress is properly constructed the
garrison will be able to resist a besieging army _six times_ as numerous
as itself. Such is the estimate of the best engineers.[48]

[Footnote 48: A good knowledge of the several subjects discussed in this
chapter may be derived from the writings of Vauban, Cormontaigne, and
Noizet de St. Paul, on the attack and defence of places and field
fortification; the several _manuels_ used in the French service on
sapping, mining, and pontoniering; Col. Pasley's experiments on the
operations of a siege, sapping, mining, &c.; Douglas's work on military
bridges; Macauley's work on field fortification; and Professor Mahan's
_Treatise on Field Fortification._ This last is undoubtedly the very
best work that has ever been written on field fortification, and every
officer going into the field should supply himself with a copy.

The following are recommended as books of reference on subjects
discussed in the three preceding chapters.

_Memorial pour la fortification permanente et passagere._ Cormontaigne.

_Defense des places._ Cormontaigne.

_Attaque des places._ Cormontaigne.

_Attaque des places._ Vauban.

_Traite des mines._ Vauban.

_Memorial pour la castrametation et la fortification passagere._
Lafitte-Clave.

_Exercice sur les fortifications._ Davigneau.

_Memorial de l'officier du genie._ A periodical of rare merit,
containing most valuable military and scientific matter. It is conducted
by officers of the French corps of engineers. It has already reached its
fourteenth number, each number forming a volume.

_Traite complet de fortification._ Noizet de St. Paul.

_Traite d'art militaire et de la fortification._ Gay de V