Falling bodies about the centre of the world; a two-bucket well
A heavy body oscillates around the earth's centre, with pulley-buckets and studies of pyramid geometry.
The right leaf (65r) is dense with Leonardo's science of the heavy body: gravity falling toward the centre of the world does not stop there at once but oscillates up and down about it in equal times, and the natural centre of weight settles only after the accidental centre has fallen. The right leaf is filled with tetrahedra and polygonal diagrams tied to a proposition on the axes of pyramids intersecting a quarter of the way toward the base. The left leaf (68v) sketches a two-bucket well whose bucket b rises full as bucket a descends empty, with a note that water runs from a to b. Further faint mirror-script and geometric line figures are present that are not part of the transcription.
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A falling heavy body oscillates about the centre of the world
Gravity falling toward the centre of the world does not stop immediately at that centre, but over time runs many times up and down about it. When the natural centre of the weight unites with the centre of the world the containing body rests without motion, and these motions are always made in equal times though never of equal length.
The natural centre falls only after the accidental centre
The natural centre of heavy bodies neither directs itself nor falls to the centre of the world except after the fall of the centre of the accidental gravity. The claim accompanies a lettered figure partly overwritten by the surrounding text.
Two-bucket well raised on pulleys
A lifting device with two buckets on a cord over pulleys: when bucket b comes back up full, bucket a goes down empty. The mechanism is drawn at the top left of the verso leaf.
Where the axes of lateral pyramids intersect
The lower axes of the lateral pyramids of any pyramidal body, arising at the third of the axis of their bases, intersect at the quarter of their length toward the base. The rule governs the many tetrahedra sketched across the sheet.
Water runs from a to b
A brief note beside a lower-left figure records the direction of flow: the water runs from a to b. It accompanies the bucket-and-pulley study on the same verso leaf.
Cluster of tetrahedra and polygons
The lower right of the recto leaf carries a series of triangulated tetrahedra together with squares and a pentagon, drawn as constructions for the centre-of-gravity and axis studies of pyramidal solids. No transcription is given for these figures.