Notes on the windlass, water pressure and communicating vessels
Short scientific propositions with a figure of communicating vessels and columns of arithmetic
The verso mixes brief scientific propositions with a small figure and columns of calculation. Leonardo states a proportion of the windlass or lever (the moved weight is to the moving force as the length of the windlass lever is to half the diameter of the drum) and asserts that water forced up an equal pipe cannot weigh more than the water that drives it. A small figure of communicating vessels marked 'acqua 20' is sketched near the lower centre, with further fragmentary notes on the pressure exerted by a reservoir of water. An aside cites Pliny on the difference between seeing a beautiful thing and an ugly one, and repeats that the worthy Florentine master has so much business he will never finish; several columns of arithmetic fill the lower right.
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Proportion of the windlass lever and its drum
Leonardo states that the weight moved bears the same proportion to the force that moves it as the length of the windlass lever bears to half the diameter found in the thickness of the windlass drum. It is a compact statement of the mechanical advantage of the capstan or windlass.
Water cannot rise weighing more than what drives it
He asserts that it is impossible for water rising up through an equal pipe into the air to be of greater weight than the weight of the water that forces it up. The proposition concerns the equilibrium of water in a pipe.
Figure of communicating vessels
A small drawing of communicating vessels is labelled 'acqua 20' (water). Accompanying fragmentary notes concern the sum of weight that a reservoir presses upon the water beneath it and the effect of drawing a pipe from a skin full of water.
Columns of arithmetic
Several columns of figures are worked out at the lower right of the sheet, including additions and multiplications such as 35, 560, 3240 summing toward 3835, and other groups of numbers.
An aside on beauty and ugliness, citing Pliny
Among the mechanical notes Leonardo pauses to ask what difference there is between seeing a beautiful thing and an ugly one, adding the instruction to cite Pliny. The note reads as a memorandum toward an argument on the value of the visual.