water

A horse or man or other thing that walks through dead water of medium depth will make that water rise up and occupy much of the shore toward which that animal directs its course.

This is clearly proved, because if you take one step within that water you will find that the water makes a wave which directs and moves itself toward the place where the walker heads, and does not stop — which gives effect to its desire — and occupies somewhat of the bank. The second step makes another wave, which does the like, and so the third, and all its steps: each one by itself makes a wave that travels to the bank, in such a way that the bank, which at first stood uncovered, is found for a long stretch covered by the water. And once you have come out of that water, you will see it return with swift course to its first place.

wine water, e f, c d, a b

Experiment with putting water into the basin f and wine into e, and note, in the percussion made by them at the intersection c d, what part at a b is of their mixture.

Shadow and light.

a b c

Make the eye as distant from the wall as the light is.

If the visual line that sees the shadow made by the light of the candle is at an equal angle to that of the shadow, the shadow will appear almost to fall beneath the body that causes it, as does the likeness of bodies mirrored by water, which appear as far beneath it as they are above. So that shadow will do, which will appear with its end to be as far beneath the plane where it is generated as the summit of the body that causes it is above that plane; as appears in the wall, c b being shadow as much as b a is body, and c b standing beneath a b.