The aforesaid tower has a diameter of 25 braccia and a circumference of 78 4/7 braccia, and its height is 20 braccia, entirely solid and of uniform thickness down to its base, which is [blank] braccia...

The diameter of the aforesaid tower is 25 braccia and its circumference 78 4/7.

And its height is 20 braccia, so that multiplying the thickness by the height gives 9360 square braccia, which, divided by 16, that is by the canna, yields 585 canne; which, at all the master's expense, walled at one ducat the canna, come to 585 ducats. The wall that forms the angle of the citadel, which is incorporated with the aforesaid tower, is 5 braccia thick, 25 long and 20 high, which is 2500 square braccia, that is 156 1/4 canne. And besides this, the void that remains within the parapet above the tower has a diameter of 10 braccia and a circumference of 31 3/7, and is 3 braccia high up to the lip of the parapet; which in sum is 225 square braccia of wall, that is 14 1/16 canne. There is also the space of the spiral staircase that mounts to the summit of the tower, and the space of the lateral defenses, which, everything taken together and deducted from the aforesaid cost of the tower, come to make up for the talus of the tower, and for the stones of the spiral stair, and for the wall that supports the bank of the ditch, whose concavity is set opposite the talus of the tower.

The walls of the ditch, which in a straight line extends between the ravelin, or gate, of Piombino and the aforesaid tower, are of various lengths. For the one that accompanies the wall of the town is 300 braccia, and the one that supports the opposite bank of the ditch is 250 braccia or thereabouts. And each must be 10 braccia high, without the foundation, of which I take no account, because in such a place it will in great part be founded upon the living rock. So that in all I find 550 braccia of length of wall, which, as I said, is 10 braccia high, which multiplied by the length of that wall are 5500 square braccia, that is 343 3/4 canne: 343 3/4 ducats.

The ditch is 275 braccia long, reckoning its longer side toward the town with the shorter toward the bank, the one being 300 and the other 250. And the width of the bottom is 21 braccia, and at the mouth 23, which above and below make 22 braccia. And its depth is 10 braccia, which multiplied by its width are 220 braccia. And these multiplied by the length of the ditch are 60,500 braccia, that is 945 20/64 canne, which are 945 20/64 ducats.