For its breadth, draw parallels to the branches of the covered way, and the re-entering places of arms, at the distance of 50 yards.
Traverses.
Those at the re-entering places of arms are erected perpendicular to the covered way; those at the salient places of arms are formed on the prolongation of the faces of the bastions, and ravelins, across the covered way; all the traverses are 6 yards thick at the top. The passages, cut out of the glacis, to enable the troops to pass round the traverses, are 4 yards wide.
Ramps.
Flank of the empty bastion.—Set off 42 yards, from the angle of the flank of the interior slope, diagonally along the slope, for the length of the ramp, to which draw a parallel line 5 yards distant, for their breadth, which mark by a perpendicular, prolonging it, and setting off 6 yards for the interior slope; to which point, from the end of the ramp, draw a line; and also from the same point draw another line parallel to the side of the ramp, and joining the interior slope of the face of the bastion.
Flanked angle of the empty bastion.—From the angle of the interior slope set off 16 yards on each side, from which points draw lines 42 yards in length diagonally along the interior slope for the length of the ramps; to which draw parallels, 4 yards distant, for their breadth; erect perpendiculars from the points (16 yards from the angle) until they intersect each other, from which point as a centre, with radius of the distance between the ramps, describe an arc joining the head of the ramps of the two faces; concentric to which, with a radius 6 yards less than the former, describe another arc, to which draw tangents from the termination of the ramps, representing their slopes.
Gorge of the full bastion.—From the angle of the interior slope, set off 16 yards on each side, from which points draw lines 42 yards in length diagonally along the interior slope; draw parallels to these at the distance of 5 yards, for the breadth of the ramps; erect perpendiculars at their head, from the intersection of which as a centre, with radius of the distance between them, describe an arc, parallel to which, with radius 6 yards less, describe another arc, to which draw tangents, completing the interior slope of the ramps.
Ravelin.—From the angle of the interior slope, set off 12 yards on each side; from these points draw lines 30 yards in length, diagonally along the interior slope, for the length of the ramps; to which draw parallels 4 yards distant for their breadth; erect perpendiculars at the commencement of the ramps, and from their intersection, as a centre, with radius of the distance from the ramps, describe an arc joining the two ramps; also from the junction of the perpendiculars draw lines to the termination of the ramps, for their slopes.
Caponniere.