System of anti-friction rollers for a flywheel
A falling weight m spins a column of graduated wheels that run on after release
The right of the page carries a tall column of overlapping circles — a train of graduated rollers or wheels — with a small weight labelled m hung on a cord at its foot, and a separate mechanism drawn in side view at lower left. Leonardo describes an anti-friction roller system in which the falling weight m spins the wheel 30 turns or more, after which it is left free to run like a spinning top. He claims the motion lasts so long after its driver stops that it seems marvelous and beyond nature, and notes that each wheel is made larger than the next so the rim of the lower one does not impede the axle of the one above.
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Roller train driven by the falling weight m
A weight marked m, hung on a cord, falls to spin the column of wheels 30 turns or more; the wheel is then left free to run like a top (trottola/calmone). Each wheel is made larger than the next, one below another, only so that the rim of the lower wheel does not rest against and impede the axle of the one above.
Motion prolonged after the driver stops
Leonardo claims the device sustains a circular motion of such durability that it seems marvelous and beyond nature, continuing to move well after the motion of its driver has ceased. To deaden the noise, the driving stone should be let fall onto straw.