Notes on percussion and obliquity, with instrument sketches
How a struck body flees toward its centre, beside compasses, wheels and other mechanisms
The transcribed passage, keyed to points labelled f, n and m, argues about impact: if the upper part is wholly sound the lower is sound only from its middle up, since from the middle down it meets the percussion required by the obliquity at which that percussion is made, while the upper part always flees back toward its centre. Around the note Leonardo drew a pair of compasses joined to a wheel, a disc, a curved vane and further mechanisms, with fainter figures and numbers not transcribed here.
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A struck body flees toward its centre
Where the upper part is entirely sound, the lower part is sound only from the middle upward, because from the middle down it awaits the percussion that the obliquity requires at the point where that percussion is made. The upper part always flees back toward its own centre.
Compasses joined to a wheel
The upper left shows a pair of dividers or compasses linked to a circular disc or wheel. A second disc and various curved elements sit below, sketched as working parts of a mechanism.
Points f, n and m
The reasoning is pinned to lettered points, the notation reading 100 - 100 - f - n - m. These mark the upper and lower portions whose soundness under impact depends on the obliquity at each point.