Perpetual-motion instruments driven by water screws
Water raised by a screw returns along a lever to feed the screw again
Two devices on this leaf are conceived to run forever on their own water. In the first, water raised through a screw is led by the pipe S to point a, runs down an equidistant lever from a to b, and returns from b to n to the same screw, forever repeating; Leonardo insists it be made wider at the foot than at the top. The second couples two screws so that screw a feeds water to screw b while screw b, with the same water, drives screw a; a further cochlea grafted on a hydraulic wheel is sketched at the left.
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Perpetual-motion device, wider at its base
Water risen through the screw arrives by the pipe S at point a, forms an equidistant lever from a to b, and returns from b to n to the first screw, always doing the same again. Above all, Leonardo notes, make it wider at the foot than at the top.
Two screws feeding each other the same water
The screw a gives its water to the screw b, and the screw b, with that same water, gives motion back to the screw a. The pair is meant to sustain its own circulation.
Cochlea grafted on a hydraulic wheel
At the left a further cochlea is grafted on a hydraulic wheel, sketched as another variant of the self-turning arrangement. No accompanying description is given for the drawing.