Four Devices for Drawing Water; Wheel-and-Axle Reckoning
Buckets, pulleys and a windlass, with the rope unwound by a seven-braccia wheel
Two mounted fragments carry studies of mechanisms for raising water: a hook and horizontal bars on the upper left, a crank-and-drum windlass below, and on the right fragment a weighted rod and two wheels on axles with hanging counterweights. The text reasons that raising a bucket takes as much motion in carrying the water as in the going itself, then reckons the rope of four water-lifts: a wheel of 7 braccia diameter yields 22 braccia of cord while its axle (half the diameter) unwinds 11 braccia, giving 33 braccia in the same time.
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The motion of raising a bucket of water
Leonardo states that every raising of a bucket has as much motion in carrying the water as in going by itself, before the note breaks off. It frames the well-bucket as a problem of moving water by mechanical effort.
Wheel-and-axle reckoning for four water-lifts
For the four water-drawing devices, a wheel 7 braccia in diameter unwinds 22 braccia of cord, while the pole (axle), of half that diameter, unwinds 11 braccia in the same time, making 33. In lifting the water the same holds: the axle drops exactly 11 braccia, the length of the band that wraps it in one full turn.
Windlass, pulleys and counterweighted wheels
The left fragment shows a hook and paired horizontal bars above a crank-driven drum, while the right fragment sets out a weighted vertical rod and two wheels mounted on axles, each with a small hanging weight. These mechanisms are drawn rather than described in the transcription.