Two cords equally loaded; three vessels pouring water
An angle bisected at a hanging weight, and a comparison of flow-rates between vessels
The upper note argues that two cords b and m bear the hanging weight n equally because the angle b n m is bisected by the central line a n, a statement of symmetric load in a suspended system. In the middle the page carries a small chain of three vessels, the last struck out, that empty one into the next. The lower note treats their flow as a rate problem: vessel a pours four jugs of water an hour and b pours three, leaving a surplus of one jug per hour.
On this page
Two cords equally loaded by the weight n
The cords b and m carry the weight n equally. Leonardo's reason is geometric: the central line a n bisects the angle b n m into two equal parts, so the load is shared symmetrically between the two cords.
Three vessels emptying one into another
Three vessels a, b and c (the last struck out) are set to discharge water from one into the next. Vessel a pours four jugs an hour and b pours three, so that one jug per hour comes to be left over.