Of Water and Weight: Floating Wood and Shapes in Currents
How figures move on water and fall through air; a wheel-train a b c turned by m
Under 'Of water and weight,' Leonardo notes that a piece of wood of even weight rests level on still water, but tips in proportion once weight is added to one end (the sentence breaks off). He then poses the problem of how various shapes — drawn in a row labelled 'course of water' — move when carried on currents of uniform or differing speed, and which part leads, which trails, which turns; the same shapes, he adds, will behave so when falling through the air along a perpendicular. At the lower right a large circle holds a train of toothed wheels a, b, c and m, whose senses of rotation and axles he describes. A small sighting/levelling instrument is also drawn at the upper right; the row of shapes carries further short labels not transcribed here.
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How various shapes move on currents of water
Leonardo asks how various figures move upon water of equal current throughout its width and length, and upon waters of differing currents, and which part of each goes in front, which behind, which always turns, and which follows straight on. The shapes studied are drawn in a row headed 'course of water.'
A beam of even weight floating level, then loaded at one end
A piece of wood of equal weight rests lying evenly on still water; but if weight is added to one of its ends, a proportion of tilt arises (the note breaks off). The same figures, Leonardo adds, will behave likewise when falling through the air along a perpendicular line toward the earth.
Train of toothed wheels a b c turned by wheel m
Wheel a turns to the right, b to the left, c also to the right, while wheel m turns left, against a. Though the axle of a is square it runs round in wheel m; b is without an axle; and m carries b and c, mounted on axles upon one of its arms, around a, which turns contrary to b.