Staggered Embrasures and an Ideal Square Fortified Town
Flanking-tower embrasures set at differing heights; a square citadel with double corner walls
Folio 91v develops the fortress theory with two flanking notes. The first rules that the gun-embrasures of flanking towers must never be set at the same height, lest the guns of one bastion strike the gunners of the embrasure opposite when both fire on escaladers, for losing the gunners loses the principal defenses. The second describes an ideal square town with a square citadel at its center, double scarped walls running from each corner over the streets, flanking ditches with roads that serve as their embankments, and gateways furnished with deep wells, iron portcullises and drawbridges; the passage breaks off and continues on folio 92r. A red-chalk bird's-eye plan of the square, corner-bastioned fortress and a small hatched sketch accompany the text.
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Embrasures of flanking towers at differing heights
In the towers that defend the walls from the flank, no embrasure should be built at the same height as another. When both fire on escaladers, an embrasure of one bastion must not fire on and kill the gunner of the embrasure opposite it, since to lose the gunners is to lose the principal defenses.
Square town with a central citadel and double corner walls
The town is square with a square fortress at its center, and from each corner a double wall runs to the corners of the town. The streets pass beneath these walls and are bent at the corners so the walls can mount artillery and sweep each street clear of enemies; each double wall is scarped with a ditch on either side.
Flanking roads, wells, portcullises and drawbridges
Beyond the ditches run two roads along their length, serving in place of the embankments, kept low so their crest does not rise to the embankment's height and expose the double wall to planted artillery. The roads are furnished with deep pits, iron portcullises, drawbridges, gates and embrasures against any enemy who breaks in.
Red-chalk plan of the square fortress
A red-chalk bird's-eye plan at the foot of the page lays out a square fortress with rounded corner bastions and a central octagonal core, set within crossing axes. A smaller hatched sketch appears beside the left column.