Construction of Field works.—Vide [Plate.]
[Fig. 1]. The redan.
Draw a base line, 60 yards, from the centre of which erect a perpendicular, 40 yards; join the terminations of the base, and perpendicular, which will form the crest of the parapet of the work.
[Fig. 2]. The lunette.
Construct a redan (vide No. 1), base 80 yards, perpendicular 50 yards: make the faces of the lunette 45 yards in length, and draw the flanks to points on the base line, 30 yards, from the perpendicular.
[Fig. 3]. The square redoubt.
Construct a square, each side 40 yards (vide [Practical Geometry]). To form additional faces when required, bisect the side of the square, draw perpendiculars inwards equal to ⅛th of the side, and join the termination of the perpendiculars, and the sides of the square, thus forming a double number of faces.
[Fig. 4]. The pentagonal redoubt.
Describe a circle, radius 30 yards, and construct a pentagon in the circle (vide [Practical Geometry]), thus forming the crest of the parapet of the redoubt.