Gearing note: a wheel and pinion of 24 and 6 teeth
Toothed wheels, pulley frames, trestles and a pyramid of shot in red chalk and ink
A note in the lower part of the sheet specifies that the teeth of a single wheel or single pinion should number 24 and 6, with the wheel one braccio in diameter. Around it, in faded red chalk and pen, are mechanical studies: a small toothed gearwheel, pulley-and-rope frames, ladder-like racks or uprights, trestle supports carrying horizontal members, and a small pyramid of stacked spheres. Further untranscribed writing appears at the lower left.
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Wheel and pinion of 24 and 6 teeth
The note fixes the teeth of a single wheel or of a single pinion at 24 and 6, and gives the wheel a diameter of one braccio. Taken as a gear pair, this describes the proportion between a wheel and its pinion.
Gearwheels, pulley frames and trestles
The sheet is filled with mechanical sketches in red chalk and pen: a small toothed gearwheel at the lower left, pulley-and-rope frames, ladder-like racks or uprights, and trestle supports carrying horizontal beams.
Ratio of the toothed counts
The paired counts 24 and 6 stand in the ratio of four to one, the proportion Leonardo sets between the wheel and its pinion. Untranscribed calculations also appear at the lower left.