FIELD FORTIFICATION.
J. W. Lowry, sc.
[Fig. 10]. The bridge head, or tête du pont.
Construct a redan, base 50 yards, perpendicular 30 yards, at an appropriate distance from the bridge, 50 yards; draw flanks, 20 yards, perpendicular to the faces, and from their termination draw lines to the river parallel to the capital of the work. To strengthen the defence of the tête du pont, construct a flèche, faces 20 yards each, and 10 yards in front of the bridge, 4 yards wide.
In the construction of bridge heads, the foregoing Figures may be employed when expedient; the simplest form, the redan, being for light bridges, and the more perfect defence, the bastioned front, or fronts, for bridges of material consequence.
[Fig. 11, 12, 13.] Lines.—Vide [Plate.]
Fig. 11. Construct a redan, base 40 yards, perpendicular 30 yards; which join by a curtain 100 yards, to a queue d’aronde.
Fig. 12. Side of square, 35 yards, and lines drawn from summit to points on the curtains 10 yards. To increase the defence of the next curtain, 100 yards, bisect it by a perpendicular, 15 yards, and draw the two faces. Lengthen the lines by cremaillères.