Water-lifting machine: the great wheel and vertical screw
Design for a drainage or water-raising engine, with a lead-and-emery rim to keep the axle true
The sheet is dominated by a large machine built around an oval great wheel driven through a geared mechanism at the right, with a central vertical screw-shaft rising from a horizontal timber base. Notes specify a rim of lead and emery on the wheel's circumference and explain that a fitting keeps the central pole from leaving the perpendicular as the wheel is raised. A further note describes a jointed 'male' piece assembled from parts stitched with thread and set with glue so as to act as one, moving from b toward a. In the Codex Atlanticus the design is classified among Leonardo's devices for lifting, for raising water and for emptying ditches.
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Lead-and-emery rim on the great wheel
Around the circumference of the large wheel Leonardo notes a 'circle of lead and emery.' This weighted, abrasive rim would add inertia and bite to the driving wheel that powers the machine.
Keeping the central pole perpendicular
A note at the foot explains that a fitting is provided so that the pole (the axle) does not leave its perpendicular as its wheel is raised. Holding the vertical alignment of the screw-shaft keeps the lifting action true.
Jointed 'male' coupling moving from b to a
The top-left note describes a maschereccio (male joint) whose less solid part sits inside; its heads are joined with thread stitches and glue so that it behaves as one piece. Its motion is to run from b toward a, so that its notch does not go against the grain.
An engine for raising water and emptying ditches
The tall screw-shaft driven by the great wheel is characteristic of Leonardo's water-lifting and drainage engines, and the sheet is catalogued among his devices for lifting, for raising water and for emptying ditches.