‹‹‹ Vitr. 1.5.6 | Table of Contents | Vitr. 1.5.8 ›››
7Then, according to the space requisite for drawing up the cohorts in military order on the rampart, another wall is to be built within the former, towards the city. The outer and inner walls are then to be connected by cross walls, disposed on the plan after the manner of the teeth of a comb or of a saw, so as to divide the pressure of the filling in earth into many and less forces, and thus prevent the walls from being thrust out.
7Then within this substructure lay a second foundation, far enough inside the first to leave ample room for cohorts in line of battle to take position on the broad top of the rampart for its defence. Having laid these two foundations at this distance from one another, build cross walls between them, uniting the outer and inner foundation, in a comb-like arrangement, set like the teeth of a saw. With this form of construction, the enormous burden of earth will be distributed into small bodies, and will not lie with all its weight in one crushing mass so as to thrust out the substructures.