A geared instrument for digging land-ditches
A frame-and-wheel excavator driven from a fixed gear, with a screw device and a long plank
The large square drawing at the upper left shows a machine built inside a triangular, tripod-like frame around a central spoked wheel, with counterweights or pans hanging at either side. Leonardo notes that this instrument is used by anyone who wishes to dig out the ditches of a plot of land, and that its toothed wheel takes its motion from a rocca (a fixed shaft) mounted below. A narrow vertical strip at the right carries a screw-and-lever mechanism, while a long horizontal strip along the bottom is noted in the transcription as devoid of writing. The Ambrosiana index attaches further untranscribed matter to the sheet, including a vain attempt at the cube root of 3000 and a note on clouds between sun and rain.
On this page
Frame-and-wheel digging instrument
A large spoked wheel is carried within a triangular frame, with weighted pans slung from the top and foot of the structure. Leonardo says its toothed wheel takes its motion from a rocca — a fixed shaft — set below it.
For digging out the ditches of a plot of land
The caption states the instrument is used by whoever wishes to excavate the ditches of a piece of ground. It presents the geared frame as a device for earth-moving and land drainage.
Screw-and-lever mechanism at right
A tall narrow strip at the right of the sheet shows a threaded screw or rack running down a slotted guide, worked by a cranked lever near its foot. It is drawn separately from the main frame.