Friction at a pivot; a water cylinder and a bell balanced
On reducing friction at the pole and counterweighting a water-filled cylinder and a bell
The note argues that only the friction of the pivot ('polo') against its seat need be reckoned, so the pivot is to be made thin and its bearing free to turn. Diagrams show a cylinder or box of water balanced by a counterweight, lettered a, t, m, f, n, and a bell likewise counterweighted. Leonardo reasons that if the pole were an ideal mathematical line, an almost infinitely small weight placed at t would move the mass of water, leaving it equally heavy about its axis.
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Friction at the pivot: make the pole thin
Here only the power of the friction between the pivot and the seat where it rubs is taken into account. Therefore the pivot is to be made thin and its support free to revolve, so that resistance to turning is least.
Cylinder of water with counterweight (a t - m f - n)
A cylinder or box holding water is balanced on a pivot against a hanging counterweight, its parts lettered a t, m f and n. A small weight set at t shifts the box of water from its first position.
Bell balanced about its pole
The bell delivers equal weights to the central line of its pole, so that were the pole an ideal mathematical line an infinitely small weight would set it moving to balance the equal weights about the axis. The water, being equal weight to the pole a, is moved little by little while remaining equally heavy around its pivot.