Elements of Military Art and Science / Or, Course Of Instruction In Strategy, Fortification, Tactics Of Battles, &C.; Embracing The Duties Of Staff, Infantry, Cavalry, Artillery, And Engineers; Adapted To The Use Of Volunteers And Militia; Third Edition; With Critical Notes On The Mexican And Crimean Wars.

by H. W. Halleck

works, is that the latter seldom present an insuperable obstacle against

assault, while the former always do. In addition, permanent works

have a better command over the adjacent country, and are more carefully

and perfectly planned. The masonry walls, which render an assault

impossible, cannot be seen from the distance, and can be destroyed

only by establishing batteries on the crest of the glacis, or the

edge of the ditch; the earthen parapet alone being visible beyond that

point, they may, until the besiegers arrive there, be regarded in the

same light as field works, with the difference that the garrison are not

harassed by the necessity of being constantly prepared to repel an