Turning a Ruined Wall into Bastions, Gateways and Gun-lines
Throw down wall a b c d, open four low gateways in b d e f, and undermine walls by cutting and propping
Two linked notes describe how to convert a battered defensive wall into an offensive earthwork. Once the defences are down, the wall a b c d is thrown to the ground, leaving b d e f, in which four wide, low gateways are opened for troops to pour through, the three intervals between them packed with rubble, branches, straw and earth into bastions mounted with artillery. Further passages lower the ground obliquely so horse and foot can descend, build covered emplacements to rake the inner ditches, and explain undermining a wall by cutting its foot over a hundred braccia and propping it with stumps and whole beams. Marginal sketches at the right show walls in section and beamed framing.
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Throwing down wall a b c d to leave b d e f
Dimensions are given as c a - 200 e 10 - d b - 200 e 6 - f e. Once the defences are ruined, the wall a b c d is to be cast to the ground, and the wall b d e f will remain standing as the base for the works that follow.
Four low gateways with rubble bastions for artillery
In the remaining wall b d e f four wide, low gateways are cut so a great multitude may enter; the three intervals are filled with rubble, branches, straw and earth to form four bastions bearing artillery. Being high, these guns can batter the enemy's defences, while covered emplacements rake the length of the inner ditches, sheltered from a rain of stones by beams and earth.
Lowering the ground and undermining by cutting and propping
Through the first and last gateway the ground is lowered by 25 braccia toward the field on a slope so horsemen and foot can descend, the spoil thrown into the inner ditch as a rampart. A wall is brought down by cutting its foot for a hundred braccia and propping it step by step with beam-stumps and, facing them, whole beams that shore it up higher.
Marginal sketches of walls and beam framing
Along the right margin are freehand sketches of walls seen in section together with framed timber structures - beams and braced frames - illustrating the ramparts and shoring described in the text. No text beyond the transcribed blocks is legible on these small drawings.