_General Remarks._—The larger the flanked angles of works, the more direct will be their fire, and that of their covert way, upon the approaches; the greater extent will they oblige the besiegers to occupy in their parallels and batteries; and the more will they oblige the besiegers to expose themselves to the fire of the fronts collateral to the one attacked. Faces of works directed to inaccessible situations, such as rivers, lakes, &c. from whence they cannot be enfiladed by ricochet batteries, add greatly to the strength of a front. If the flanked angle of a ravelin be so advanced as to see in reverse any battery erected upon the crest of the glacis, or in the covert way of the bastions, it will increase the strength of that front; because it will oblige the besiegers to gain possession of the ravelin, before they can make any lodgement, from which they can batter the bastions. This is the case in Cormontaigne’s system: and a place thus fortified, obliges the besiegers to attack and gain two ravelins, to get at the bastion between them. Beside, if this system be applied to a right line, or to a polygon of many sides, the prolongations of the faces of the bastions, will be intercepted by the flanked angle of the ravelins, and consequently make the establishment of enfilading batteries against them very difficult. A work which admits of a breach being made in it (particularly the body of the place) at a distance, very much facilitates its being taken. The ditch of the ravelin affords an opening through which the besiegers may make a breach in the face of the bastion, from the glacis, opposite the flanked angle of the ravelin, and is therefore subject to this defect. A counterguard before the bastion, lessens this evil, by transferring the breach from the body of the place to the ravelin; but it requires a counterguard also before the ravelin, effectually to cure it. A crown or horn work also produces this evil; its remedy was given, in speaking of those works. The direction of the flanks or faces of a work is not so material as relating to the fire of artillery, as to that of musquetry; for artillery is never fired without being pointed, but musquetry is fired mechanically, and perpendicular to the parapet, without much attention to the object to be struck. A work in the neighbourhood of a height must be defiladed[7] from that height, that is, instead of being built upon a horizontal plane, it must be erected upon an imaginary inclined plane, passing from somewhere in the interior of that work, over the most commanding points of the height: and every part of the works must bear the same relation to this inclined plane, that they would do, to a horizontal plane in a level country.