7. The parts flanked ought to be within musket fire of their flanking parts.
8. The fire ought to be equally distributed, that every part of the work may be equally defended.
9. The work ought to be equally strong in all its parts, that it may everywhere equally resist the assaults of the enemy; and the parapet should be thick enough to withstand the shot fired against it.
10. The dimensions of the parapet should not only be sufficient to secure, and cover the troops within the work, but ought also to be of such a form as to afford a full view of the enemy in his approach; and at the same time discover, as little as possible, the men employed for its defence.
Capacity of Field works.
The perimeter of a work, and the number of men to defend it, should bear a just proportion to each other, one yard being allowed for each man, or for each file of men, according to the nature, and object of the work.
In calculating the area of enclosed field works, 10 square feet may generally be estimated for each man, and 324 square feet for each gun, and its stores.
Content of Field works.
In square redoubts, or works having salient angles, if the areas of the sections of the parapet, and ditch, are made nearly equal, there will be too much earth; were the angles of the plan re-entering, instead of salient, the result would be reversed. Bearing this in mind, previous to commencing the excavation of the ditch, a correct calculation must be made to prevent any excess, or deficiency of earth for the parapet, and banquette.
Rules.