Breaches in counter-guards, lunettes, mantcaux, Sze. are laid as in the demi-lunes, or nearer to their saliant angles.
At the same time, with these breaching batteries, dis mounting batteries are also constructed for destroying the flanks. The breaching as well as the dismounting bat teries are constrncted by the aid of the sappc, in a manner similar to that before described. But sand bags and wool bags are here also of considerable advantage, and where they are to be had, they should always be used. The fire of these dismounting and breaching batteries is begun as soon as they are finished, but never sooner, that they may not be exposed too much, while they are in an unfinished state. The shots of one battery are fired at the same time, and directed at about one-half of the height of the revete ment. Every embrasure is to be advantageously blinded with a gabien, a wool-sack, or a bundle of fascines, while the men are charging the guns.
During the discharge of the guns for dismounting the rampart and making breaches, the passage into the covered way is to be formed by the sappe, and from that the way to the fosse is made, either by a subterrancous passage, or by the double and covered sappe. When the subtcrrancous passage is formed, it is to be lined and covered with wood, and carried on to the revetemem of the counterscarpc. This is penetrated either by a small mine, or by piercing it, and making an entrance, which is to come about two feet above the furface of the water, or as much above the ground of a dry fosse.
The passage over the fosse is differently constructed, ac cording to the nature of the fosse. A dry fosse inay be pass ed by a double or by a covered sappe ; a wet fosse where the water does not flow, by a fascine clam ; and a fosse where there is a current, by a kind of fascine dam con structed on scaffolds, to let the water pass by.
The sappe over a dry ditch is made, as described above, either by mines, or like a double or a covered sappe.
The clam over a wet ditch, where there is no current, has two parapets ; one at each side, if the enemy's fire is to be feared in passing the fosse, even though all his guns at this time should be dismounted, or at least unfit for use on the attacked side. The dam is regularly and succes
sively constructed, by forming a layer of fascines, and cov ering Item with earth, and continuing with this till it be sufficiently high ; then the parapet is constructed, a new part begun, and the work proceeds thus till the whole is finished.
A dam over a fosse which has a current, is more difficult. The first thing is to try whether the current cannot be stop ped, or the water let off. When this is impossible, the scaffolds are placed gradually, the intervals are filled with fascines, the upper part formed also with fascines and earth, and then the parapet constructed. The weak parts are then strengthened, so as to guard as much as possible against all accidents.
The last part of such a dam generally is a bridge, which is constructed of long rafters, and covered with fascines and earth like the other parts of the dam.
When the dam or passage over the fosse is completed, the assault is determined upon, and secretly and unexpect edly undertaken an hour before day-break. The outworks generally are taken before the bastions can be assaulted, but sometimes, and as often as circumstances allow it, the outworks are either passed, or the bastion and the out works attacked at the same time. As soon as a practica ble breach has been made in the rampart, a sufficient num ber of volunteers assault the work,,and in general soon get possession of the place. if the garrison retires to an en trenchment, that also must be immediately assailed ; but if this cannot be done, the soldiers lie down, and cover them scves with wool-sacks, till the lodgement is formed by a number of workmen ordered for this purpose to accom pany the soldiers who make the assault.
If this lodgement be practicable for receiving troops, it is directly to be occupied, and this must be done by day break at latest, that the men may not suffer too much from the fire of the enemy's small arms. Such lodgements are most expeditiously formed of sand-bags, wooi-sacks, &c.