Large bastions have the advantage of small ones, for this palpable reason; the bastion being considered the weakest part of the body of a place, is always attacked; when there is room for troops, cannon and mortars, its natural weakness is greatly remedied.
Gorge of a bastion, the interval between the extremity of one flank and that of the next.
Flat bastion. When a bastion upon a right line is so constructed, that its demi-gorges do not form an angle, it is called a flat bastion.
Gorge of a flat bastion, is a right line, which terminates the distance between two flanks.
| Solid bastion, | - | |
| Full bastion, |
A bastion is said to be solid or full, when the level ground within is even with the rampart; that is, when the inside is quite level, the parapet being only more elevated than the rest. Solid bastions have this advantage over others, that they afford earth enough to make a retrenchment, in case the enemy lodge themselves on the top of the bastion, and the besieged are resolved to dispute every inch of ground.
| Hollow bastion, | - | |
| Empty bastion, |
is that where the level ground within is much lower than the rampart, or that part next to the parapet, where the troops are placed to defend the bastion. The disadvantage of these kinds of bastions is, the earth being so low, that when an enemy is once lodged on the rampart, there is no making a retrenchment towards the centre, but what will be under the fire of the besiegers.
Detached bastion, is that which is separated or cut off from the body of the place, and differs from a half moon, whose rampart and parapet are lower, and not so thick as those of the place, having the same proportion with the works of the place. Counter-guards with flanks are sometimes called detached bastions.
Cut bastion, is that whose saliant angle or point is cut off, instead of which it has a re-entering angle, or an angle inwards. It is used, either when the angle would, without such a contrivance, be too acute, or when water, or some other impediment, prevents the bastion from being carried to its full extent.