Fig. 13. Base 100 yards; crochet, base 5 yards; perpendicular 20 yards.
Lines, continuous, are formed by a modification of redans, lunettes, curtains, &c., dependent on the nature of the ground, and the means of defence.
Lines, with intervals, are formed by detached redans, lunettes, &c., within range of each other; the rear works flanking those in front.
Bridges, and passages into field works are from 6 feet, to 12 feet wide, according to the requirements.
Traverses are placed about 9 feet from the slope of the banquette, their length being so regulated as to exclude from the view of the enemy the interior of the field work.
The nature, and form of the field work, or lines, required for the defence of a post, &c., &c., having been determined, the perimeter may be laid down, in conformity to the construction detailed in the foregoing figures: after which the requisite dimensions of the parapet, ditch, &c., (dependent, of course, on the nature of the enemy’s ordnance) must be taken into consideration, and the quantity of earthwork computed by the Rules, [page 245], or by those in Practical Geometry. The following Table will, however, in many cases be found useful; and, by a judicious adaptation of it, much time may be saved in the computation, and construction of field works.
Table,
showing the dimensions, in feet; and the superficial content of earth of banquettes, parapets, and ditches, of field works.
Key:
A = Number.
B = Base of slope.
C = Tread.
D = Height.
E = Base.
F = Superficial content.
G = Berm.
H = Breadth at top.
I = Escarp slope.
J = Counterscarp slope.
K = Depth.