Self-Acting Water-Raising Instrument
Vessels, cones, valves and floats to lift water, with lever ratios and a viewpoint figure
A dense study for a self-acting hydraulic 'instrument' that raises water by letting it fall onto air trapped in a large vessel and drive it through cones and pipes; Leonardo remarks that Amboise has a royal fountain without water. Float-and-valve details show how upper and lower vents must open and close in the same instant, and a margin calculation gives the mover eight units of power against one of resistance. He repeatedly notes that all rubbing parts should be made of crystal or other hard stone. A small figure of a man with visual lines in the lower-right corner is said to be drawn to a fixed eye and seen from an unobstructed viewpoint.
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Water falling onto trapped air to be raised
The proposed instrument has water descend onto the air enclosed in the largest vessel; when the two cones are moved half their motion, their sheath-perforations stay half open, and the weight of water in the opposite pipes drags the air after it. Leonardo objects that the conduit would end up full of air, and adds that Amboise has a royal fountain without water.
Float acting as a balance to open and close valves
As the largest vessel nearly empties, float b gains weight and sinks like a balance arm, releasing a float that lifts the rod and shuts off the upper water once the bottom is closed. The vessel then reopens above while reclosing below until it is full; the largest cistern is not to be emptied entirely.
Eight of power against one of resistance
The margin figure sets a b at 110 and c d at 100, with the mover's lever 4 and its counter-lever 1/2, giving eight of power against one of resistance. e f is called the mover of the whole, the motion of the first cause.
Upper and lower vents alternating in one instant
When the upper vent opens the lower must close in the same instant, with speed and percussion, and the reverse when the lower opens. The vent of the emptying vessel opens from outside inward to restore the vacuum, while that of the filling vessel opens from inside outward.
Third and fourth methods with cones and floats
In the fourth method the vessel empties below and closes above, the float's motion blocked by the resistance of the lower cone b. In the third, the descent of the float with its a b arises when the weights o p sink upon the air.
Figure of a man drawn to a fixed eye
In the lower-right corner a small figure of a man is set out with visual lines. Leonardo notes that the figure is made to the fixed eye and is seen from an unobstructed position.