Avoid destroying the natural appearance of the wood; do not cut the trees and brush on a certain depth, but cut off branches where necessary to obtain a field of fire. Behind this strip cut the brush and small trees so as to make a path 3 to 4 yards wide. Construct a trench behind the mask of trees. The parapet can be raised up to 2 or even 3 feet. Construct abatis on the parts of the border of the wood, where it will not interfere with the fire.
Walls:
Plate 27y.—Arrangement of a wall 2 feet 8 inches high.
Plate 27z.—Arrangement of a wall 8 feet high.