Canal and river survey of the Romorantin country
Gradient calculations, a hydrographic map of the region, and a note of returning from Romorantin to Amboise
The sheet is dominated by a branching hydrographic map of rivers in the Romorantin district of France, labelled with place names such as Remorantin, Tours, Amboise, the Era, the Cher (Scier) and the Sauldre (Sodro). The notes work out the fall needed for canal water, define measures (the trabocco, braccio and once), and give an instruction to test the level of a canal to be dug from the Era to Romorantin. A short personal memorandum records returning from Romorantin to Amboise on the eve of St Anthony, the king having left two days earlier. Additional untranscribed passages in Leonardo's mirror-script are also present on the sheet and are left untranslated here.
On this page
River map of the Romorantin country
A branching network of watercourses is drawn down the sheet and labelled with place names. The right-hand sketch names Moti Ricardo, Remorantin, Tors, Ambosa and Bres; the left-hand sketch names the Era and Scier (Cher) rivers, Villafranca, the Ponte Sodro and the Sodro (Sauldre) river.
Calculating the fall of water in the canals
A trabocco is set at four braccia, a mile at three thousand braccia, the braccio at twelve once, and the fall of canal water at two once per hundred trabocchi. From this he concludes that fifteen once of fall give due motion to the currents, that is one braccio and a half per mile, and applies the reasoning to water drawn from the river of Villafranca and lent to the Remolontino.
Test the level of the canal from the Era to Romorantin
An instruction to make a trial of the level of the canal that is to be led from the Era to Remolontino, using a canal one braccio wide and one braccio deep.
Return from Romorantin to Amboise
On the eve of Saint Anthony he returned from Romorantin to Amboise, the king having departed two days earlier from Romorantin.
Further untranscribed writing on the sheet
Additional passages in Leonardo's mirror-script appear on the leaf, including a block at the upper right beside the river drawings and a short note at the left, which are not part of the present transcription and are left untranslated.