496 MACHETECHNICS. 



the bottom of the ditch, and screened by the outworks, it is com- 

 pletely protected from the distant fire of the enemy. The exterior 

 wall of the ditch, supporting the earth on the outside, is called the 

 counterscarp. 



Instead of having a simple circular or polygonal contour, the scarp 

 is broken inward on -each side, (PL XI. Fig. 5), producing a series 

 of bastions, (aMc. &c.), connected with each other by curtains, 

 (cd. &c), so as to form a complete enclosure. Each curtain, with a 

 half bastion on each side of it, forms a bastioned front ; (JIB] ; the 

 parts of which have important relations to each other. The faces, 

 (M, and Be,) and the curtain, (cd) are chiefly intended for firing 

 upon the enemy at a distance : but the flanks, (be, and de,) are 

 especially intended for the defence of the ditch, in case that the 

 enemy should enter it ; as each flank may enfilade the opposite half 

 of the ditch, on that front, with a fire of grape or cannister shot. 

 Thus, each part of the work is protected by some other part, which 

 is not likely to be exposed to an attack at the same time : but, for 

 this object, it is necessary that the distance of any one flank from the 

 salient angle which it is to defend, should not be greater than the 

 effective range of small shot, fired from the flank carronades. 



The interior area of the fort is called the parade ; between which 

 and the ditch, is the rampart, of which the scarp forms the exterior 

 face.* The rampart is elevated, in order to overlook the outworks ; 

 and to protect the men, or even the buildings, in the interior, from 

 the enemy's fire. The top of the rampart consists of two parts ; 

 the terrepleine, or interior part, (dotted in Fig. 5), on which the 

 guns are mounted ; and the parapet, which is the exterior and 

 highest part, to shelter the guns and men on the terrepleine. 

 The parapet has a superior and exterior slope, as in field works ; but 

 the breast height is frequently a wall of masonry. Instead of making 

 the whole rampart of solid earth, it is customary, in fortresses, to 

 construct vaults or rooms in it, to protect the men during a siege. 

 Piers are built, running back from the scarp wall to the interior of 

 the rampart, which in this case becomes the parade wall ; and these 

 piers support arches, which are covered with earth ; so that the guns 

 stand above them ; leaving spacious rooms, called casemates, under- 

 neath. Some of these casemates are used for guns ; which then fire 

 through embrasures, or openings, in the scarp wall : some are used 

 for magazines or store rooms; and others, fitted with windows in the 

 scarp and parade walls, with fireplaces and other fixtures, are used 

 as quarters for the officers, and barracks for the men. 



Of the outworks, which serve to retard the enemy's approach, the 

 principal is the demilune, or ravelin, (Fig. 5. D) ; the faces of 

 which have an advanced and cross fire upon the environs, without 

 being so high as to mask the fires of the main work. The ditch of 

 the demilune, (O), is connected with the main ditch ; but not quite 

 so deep. Outside of the demilune, is the covert way, (J7 7 ), along 

 which guns are mounted, and men stationed, to fire upon the enemy; 

 without intercepting the fire of the mainwork. From the breast 



* This is more fully represented in Fig. 6 ; which represents a section of the 

 fort along the line YDZ, of Fig. 5 ; as shown by the correspondence of the letters. 





