Kinds of eddy and how falling waters combine
Eddies slow or swift at their center — depositing hillocks or boring wells — and waters joined by reflected motion
Leonardo classifies eddies (retrosi): some are slower in the middle than at the sides, some swifter, and others reverse their first motion. The slow-centered eddy of great circuit deposits material in the middle of its circle, leaving it like a hillock, while the swift-centered eddy drives air and water to its bottom, hollowing and boring it like a well. A further diagram (m, K, h, n) shows how water falling from m to h drags along the water falling from K to h through the reflected motion h n — which it would not do unless the percussion of K h on the bottom broke the water's course at h.
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Three kinds of eddy (retroso)
Of eddies, some are slower in the middle than at the sides; some are swifter in the middle than at the sides; and others turn their first motion in the contrary direction.
Eddies that deposit hillocks or bore wells
The eddy of great circuit, slower in the middle than at the sides, deposits much material in the middle of its circle and leaves it like a hillock. The eddy swift in the middle carries air and water to its bottom, hollowing and boring it like a well.
Falling waters combined by reflected motion (m, K, h, n)
The water falling from m to h carries with it the water falling from K to h through the reflected motion h n. It would not do so unless the percussion of K h upon the bottom broke the course of the water at h.