Notebook on Mechanics and Natural Philosophy

Water that moves atop other water of its same kind is lighter the further it is removed from its center. I am speaking of the center of the rolling motion original: "moto rotolante"; Leonardo conceptualizes the movement of waves or surface currents as a series of rolling or rotating cylinders of water. of the surface of the water rolled above said water.

Let the center of d be the weight of the water that moves above other water, and let the center n be the weight of an identical quantity of water that is at rest, and let m be the center of the earth.
I say that the water d will be lighter than the water n by as much as the line d-m is longer than the line n-m. For it is manifest that the further a weight is removed from the center of its rolling motion, the more lightness it acquires, because the circumference of the circle of that water—

How water that moves over other water of its very same kind is lighter the further it is removed from the center of the earth.

Let a be the center of a rolling mass of water, and let the other water n be at rest. I say that water a will be lighter than water n by as much as the line a-n is further removed from the line m-n, where m shall be the center of the earth; this is because the line a-n is the radius of the circumference of the circle of that water rolling above the radius n-m, which is the radius of the earth.

A geometric diagram consisting of a rectangle with a diagonal line. Points are labeled A and S. Two small circles are at the base of the rectangle. An arc connects the vertical sides. A vertical line with a small weight at the end is drawn to the right of the diagram.

Water that moves shall be so much lighter as it is further removed from its center.

A small circle resting on a horizontal line.

A circle with a horizontal diameter and two vertical lines extending downwards from the sides, resembling a pulley or a cross-section of a cylinder.

Rolling water does not have the weight of still water, because the weight is resolved into the circumscribing motion. circunscriptibile: motion that follows a circular or enclosed path, effectively "spending" its downward force as rotational energy.