Another method of strengthening a place, or rather of obstructing the enemy, is to plant large branches of trees on the counterscarpe, on the berme, or behind the glacis. The last is perhaps the best position, as they are defended from the enemy's fire. Chevaux de frises may be substi tuted for branches, but they are more difficult to be pro cured.
Besides these, various other obstructions may be employ ed to prevent or retard the enemy's approach ; as stakes driven into the ground for a considerable space together, herses fixed in an inclined position, caltrons, &c. These, of cool se, are to be adopted or not, as circumstances may re quire. In some cases they may be of little use.
In field fortification, fougasses, or small mines, are fre quently of great advantage, provided they be carefully at tended to, and fired at the proper moment. The fourneaux of these mines are laid twenty or thirty paces before the counterscarpe, and the saucisson, or long thin bag of pow der for firing them, is conveyed by means of an auget, or wooden trunk. Mines can only be useful• when the pow der can be kept dry for some time. Large mines for out works are too expensive, and of less use than smaller ones. The best position for them is before the saliant, as there the attack is more likely to be made.
The fosse of a fleche is defended at its gorge by capon niers, or by palisadoes three to four inches thick, having, at the distance of every 21 feet, an opening like a loop hole, or a low palisade, which answers the same purpose. The entrance to the work may he concealed from the ene my by the palisade, on one side projecting before that on the other. Such a defence, however, can only be used where a work cannot be attacked in its gorge. A stronger defence of the same kind, for the gorge of a fosse, is by means of two rows of palisades, fastened at top by cross rafters, on which • e placed fascines, and the whole cover ed with earth. Montalembert has proposed to construct these with a saliant angle, and, that they may be less ex posed, to place the loop holes about two feet above the bottom of the fosse, but lower than the glacis, Such capon niers have a subterraneous communication with the in terior, by a passage lined with poles and boards, and are surrounded by an abattis, or by trappes de loops, to pre vent the enemy from approaching them. Similar capon
niers arc places in the saliant angle of the counterscarpe, ten feet distant from the ditch, which is there enlarged to twelve feet in width towards the field, and lined with poles, boards, Ez.c. The loop holes of these caponniers are form ed so as to enflank the glacis, and the gorge towards the ditch is shut by strong palisades. They are also surround ed, like the others, with trappes de loops, or an abattis. It may be observed of all these caponniers, however, that they cannot be made to hold out long against a cannonade, and are therefore useful only when that is not to be ex pected.
In large forts, it is sometimes of advantage to have a reduit to which the garrison may retire, and which, of course, may be large enough to contain them, till such time as assistance, or favourable terms of capitulation, can be procured, in case the fort should be taken. If the reduit is constructed of earth, it will require no greater profile, than merely to command the work before it. If it be made of timber, it is to have loop-holes, by which the soldiers may fire on the enemy, without being exposed to his fire : and it should be so constructed as to enflank every part of the fort. The cover must, if possible, be snell-proof.
Similar to this is the work proposed by C. Muller, con sisting of a redoubt, with four small bastions at its saliant angles, the diagonals forming a sort of caponniers of wood work. In the middle, where these caponniers meet, this wood-work has two stories, with loop-holes in the walls. All such works, however, being of wood, are easily de stroyed.
The most advantageous kind of reduits are block-houses. These have walls formed of rafters, from one to three feet thick ; and roofs, consisting of two layers of the same, overlaid with fascines, and covered with earth, so as to be shell-proof. Such houses may even supply the place of a fort, and are particularly useful in winter. The access is by a ladder to the top, or by a side door, which is sufficiently defended by palisades, and also by abattis or trappes de loops around it.