Of objects of various thicknesses placed transversely in the equal course of the water, and turned with equal inclination toward one of the banks, that one will dam back more water which, with a greater secondary obliquity, inclines more against the coming of the waters.

The air that restores the emptying of the water which is poured from its vessel enters through the mouth of that vessel and passes to the surface of the water by the shortest way.

Of objects of equal thickness placed in water, of equal obliquity and set transversely across the course of the river, and inclined with various obliquities to the bank of that river, the one that is more oblique will dam back more water to that course.

Of the obliquities of equal thickness placed at equal obliquity of water and inclining toward one of the banks with equal obliquity, that one will dam back more water which is more oblique to the line of the river's course.

That part of the object which rises above the common course of the water will be more occupied by the rebound of the water that strikes it, whose obliquity is more similar to the obliquity of the said course of the water.

Of that columnar object which projects out of the course of the water, the greater part will be occupied whose obliquity is more similar to that of the water in which it stands.

Of the object that rises above the water, the greater part will be occupied by the rebound of the water that strikes it, whose obliquity is more similar to the obliquity of the aforesaid course of the water.