Bird's-eye plan of a fortified circuit with old walls and a ravelin
A dimensioned survey of a fortress enceinte measured in canne
A bird's-eye plan traces the circuit of a fortified place, its curtain walls and corner towers laid out and dimensioned throughout in canne. The notes distinguish an outlying ravelin and a stretch of older walls, and record the lengths of successive runs of wall and their crosswise thicknesses. A projecting corner fortification is set out with its own series of measurements. The plan occupies the whole irregularly cut leaf.
On this page
Dimensioned circuit of walls
The first run of wall is measured at 20, 70, 7 and 70 canne, with crosswise dimensions of 6 and 2 canne. Successive stretches are gauged in the same way, one of them 60½ canne long, building up a surveyed plan of the whole enceinte.
Old walls and ravelin
An inner note marks a section of 'old walls' and a detached 'ravelin' (rivellino), with adjoining measurements of 2 and 5 canne. These identify the existing and outwork defences within the circuit.
Corner fortification
A projecting corner work is dimensioned with the series 31, 27, 10, 32½ and 26 canne, fixing the reach of the angle bastion of the circuit.