This is a drawing by Leonardo da Vinci, one of several models of self-sustaining rotaries, which he proposed for perpetual motion. His experiments, however, displeased him and he declared: "Oh, ye seekers after perpetual motion, how many vain chimeras have you pursued? Go and take your place with the gold-seeking alchemists."

Many men of science have nonetheless pursued it. Pascal, the logician, pursued it.

One Proud American Inventor

In America the pursuit for the perpetual motion machine was popular throughout the nineteenth century, and several dozen hopeful patents were issued by the U.S. government for its invention, none of which were ever manufactured.