CHAPTER XIII.
PERMANENT FORTIFICATIONS.
_Fortification_ is defined,--the art of disposing the ground in such a manner as to enable a small number of troops to resist a larger army the longest time possible.

If the work be placed in a position of much importance, and its materials be of a durable character, it is called permanent; if otherwise, it receives the appellation of _field_, or _temporary_.

Fieldworks are properly confined to operations of a single campaign, and are used to strengthen positions which are to be occupied only for a short period.

Generally these works are of earth, thrown up by the troops in a single day.

They are intimately connected with a system of permanent fortifications, but from the facility of their construction, no provision need be made for them before the actual breaking out of war.