The descent of the heavy body is not toward the center because it is drawn by it, nor because such a heavy body desires to join with that center, but because the medium cannot sustain it. I say the descent of the heaviness of water is not caused by the center of the world drawing it to itself, nor because such heaviness desires to join with the said center, nor because its element draws it to itself by the shortest way. If the center of the world drew it to itself, that water would always move toward that center, and if it could not move, at least it would always weigh and press upon whatever obstacle impeded its descent. But the opposite of both is seen, because whoever lets water fall upon the earth, it immediately loses its weight and its desire to descend. And that it gives no heaviness upon its support is seen in the bottom of the water of marshes, where the mud is so very light, almost of the subtlety of water, that it stays floating like a mist between the ground and the water of the marsh. This would not be so if such water weighed upon that bottom. Again, one sees the tips of the most slender grasses detach themselves from the bottom of these marshes and penetrate through the water toward its surface, as if surrounded by air. But if the water weighed upon its bottom, it would also weigh upon the tips of such grasses, and they could not be penetrated by them; rather it would hold them bent and flattened together with the compacted earth. Again, the heaviness of great buildings does not weigh upon their supports, as is seen in the soils drawn out from under their foundations, which is no less rarefied than if it were situated under the air.

The pyramidal descent of the heavy body, made without impetus, will be at a right angle before it joins the center of the world. Every pyramidal heavy body has 3 centers, of which the first is the center of natural gravity a, the 2nd is the center of accidental gravity, that is b, the 3rd is the center of its magnitude, which is c. The center of the natural gravity b will move to find the center of the world p along the line b p, always keeping 2 weights at equal height above itself; and when it is joined to the center of natural gravity...

The site of equality is that which holds the centers of the heavy bodies, placed upon the ends of the balance at equal heights, above the center of the world.

It is impossible to make the angles a, b equal upon one and the same base without the pyramids being of equal length. When two triangles arise upon one and the same base, such will be the proportion from angle to angle as is from the one height to the other.

The water a will lose its weight in falling into the water n, even though it were very greatly distant from the sphere of its element b.