Water machines: float-valve cistern, bellows and mercury tube
Hydraulic and pneumatic devices with a self-acting reservoir, siphons, a bellows and a mercury-and-oil tube
A sheet of hydraulic and pneumatic apparatus in brown ink: water-wheels, U-shaped siphon vessels, a bellows (mantaco), and a tube charged with mercury and oil. Leonardo describes a cistern (bottino) whose small doors are unlatched by a floating gourd when it fills, needing air admitted through a spiracle, and gives a lever-and-counter-lever rule for how far water can be raised. A short list of people, animals and craft is jotted in the upper corner, and diagram letters a, b, c and d are used across the water and tube figures.
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Self-acting cistern with floating gourd valve
A reservoir (bottino) has small doors unlatched by a gourd that rises afloat when it fills. Leonardo explains it must be filled with air through spiracle c, because the reservoir b cannot supply that air itself: the air cannot penetrate against the weight of water falling through door a, and it finds an easy exit through the mouth of the bellows d.
Bellows and blowpipe tube
A bellows is labelled 'mantaco' on the upper margin, and a curved tube is marked 'blowpipe (cerbottana), oil, water, b', with the instruction that the tube be of uniform bore from beginning to end. These pneumatic fittings work with the cistern and siphon vessels around them.
Mercury-and-oil tube
A figure lettered c, d, a, b shows a tube charged with mercury and oil, with the note that when a is near a finger's height of mercury, d has descended into a. A neighbouring curved tube is marked 'oil, good'. The device gauges the balance of the two fluids in a closed bore.
Lever rule for raising water with a wheel
Beneath a water-wheel a rule states that if the water rises a hundred braccia and returns fifty, then with a lever of a hundred braccia and a counter-lever of one braccio it will raise a quarter of a braccio. It relates the fall and return of water to the mechanical advantage of the lever.
List of people, animals and craft
In the upper corner is a plain vertical list: Jews, children, men, old men, harlots, donkeys, mules, buffaloes, horses, oxen, pigs, ship, boats. It is a bare enumeration with no accompanying explanation.