Hydraulic wheel and eddies below a fall of water
Red-chalk sketch of a paddle wheel above a note on where eddies form
A red-chalk drawing shows a wheel turning on a horizontal axle, its rim fitted with angled paddles or scoops of the kind driven by running water. Above it a short column of figures records a calculation, and below the wheel a single line of mirror-script observes where eddies arise in falling water. The note states that the swirls made by water after the breadth of its fall lie between the surface and the bed, ranging up and down.
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Where eddies form after a fall of water
The eddies made by the water after the breadth of its fall will lie between the surface and the bottom, ranging both up and down. Leonardo places the turbulence not at the surface alone but throughout the depth of the stream.
Paddle wheel on a horizontal axle
A wheel is drawn in red chalk, mounted on a cross-shaped axle with a central hub. Angled vanes or scoops project from part of its rim, the arrangement of a wheel meant to be turned by a current of water.
Column of figures
At the top of the leaf stands a small worked calculation: paired figures, then 500 and 83, 66 3 15, and the running totals 12, 30, 15 and 180. The numbers are set out as a computation rather than as continuous prose.