Levelling of the Arno and the excavation works at Piombino
Survey levels, compass bearings, ditch-digging costs and wall profiles
This opening (folios 1v-2r) gathers Leonardo's field-notes for the Arno survey and the fortification works at Piombino, written in mirror script around red-chalk sketches. A heading records a levelling of the Arno taken on the feast of the Magdalen in 1503, with a long column of measured levels, while compass bearings fix the river-mouth, Pisa, its tower and the fortress of La Verruca. Notes 'on workmanship' price the excavation of the Piombino ditch by the cubic canna and the building of walls by the canna, and four small profiles of a wall are compared as good, bad, better and worst. Marginal memoranda list reminders - a lodestone, understanding the winds, sighting Elba, flint and rope-lashings - and a maxim observes that heavier bodies slide more readily than lighter ones.
On this page
Levelling of the Arno, 1503
A note records a levelling (survey) of the Arno made on the day of the Magdalen, 22 July 1503, set beside a long column of figures giving the measured levels. The readings run from small fractions up to twenty-three.
Excavating the ditch of Piombino, priced by the cubic canna
Under the heading 'on workmanship' the sheet prices the digging of earth for the ditch of Piombino: five lire the cubic canna a-b, and three lire and one-seventh the cubic canna g-a, with baskets and ironwork supplied by the lord, and four lire the wall at the master's charge.
Four wall profiles: good, bad, better, worst
Four small profiles of a wall or scarp are drawn side by side and rated beneath as good, bad, better and worst, comparing their cross-sections. The judgement sits among the notes on walling and on excavating the Piombino ditch.
Compass bearings to Pisa, its tower and La Verruca
A sighting note fixes landmarks by compass bearing: the river-mouth lies half a point from west toward south-west (libeccio), with Pisa, the Torre de Pagone and Verruca ranged along the same westerly-to-south-west line.
Costs of walling reckoned by the canna
Several price notes reckon the wall by the canna: four lire the canna, or three lire when done at the builder's own charge, and a total of twenty lire. The figures stand among the Piombino excavation costs.