Make the passage of this work 30 feet wide, including the banquette on each side; the superior slope of each parapet terminates at 20 yards’ distance.
Bridges, and communications.
These are about 14 feet wide.
Stairs, or Pas de souris.
These steps of masonry are made at the gorges of the several works, and at the salient, and re-entering angles of the counterscarp. Those at the salients are generally 24 feet long, and at the re-entering angles 30 feet; they are 5 feet wide, and their steps 1 foot distant from each other.
Sally-ports.
These passages, cut through the glacis, are about 12 feet wide, and 18 feet long.
Profile of Vauban’s 1st System.
J. W. Lowry, sc.