Weights on cords: a halved angle doubles the load
A cord over a graduated arc, showing how a smaller angle burdens the cord more
A weighted box hangs from a cord that runs across a semicircular graduated arc, with a long line rising to the corner. Leonardo argues that when angle b c n equalled angle a b n the two cord-ends carried equal load, as much on a as on r. Here, because the angle is only half as large as before, that cord is loaded with twice the weight. The note is headed as confirmed by experiment.
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Halving the cord's angle doubles the weight it must bear
When the angle b c n equalled the angle a b n, a sustained as much weight as r, so the two ends of the cords were loaded equally. But here, because the angle is smaller by half than before, its cord is loaded with double the weight.