The Center of the Weight Rests Below the Pole
Leonardo's refutation of perpetual motion, and his rebuke to its speculators
A plain circle with a marked central pole, a radius dropped to the bottom, and a small ring for a weight at the upper right illustrates the general law. Leonardo states that whatever weight drives a wheel, the centre of that weight must come to rest below the centre of its pole, and that no turning instrument human ingenuity can build can remedy this. He closes with his famous rebuke to the seekers of perpetual motion, telling them their vain designs make them fit company for the seekers after gold.
On this page
The center of the driving weight comes to rest below the pole
Whatever weight is attached to a wheel as the cause of its motion, the centre of that weight will without any doubt come to rest below the centre of its pole; and no instrument that human ingenuity can build, turning upon its pole, will be able to remedy this effect.
Rebuke to the speculators on perpetual motion
Leonardo apostrophises the seekers of perpetual motion: how many vain designs they have created in a like quest, and he bids them go and join the seekers after gold.
Circle with central pole and small weight
The diagram reduces the problem to a single circle: a marked centre or pole with a radius dropped to the lowest point, and a small ring for the driving weight set high at the right.