Perpetual motion machine described in about 1664 by Ulrich von Cranach of Hamburg. Iron balls drive the water wheel that operates the Archimedean screw that raises the balls up again. Cranach claimed it would operate pumps for mines, and insisted that it stood in water. This would have increased energy losses, but was probably necessary to hide a secret driving mechanism. Engraving from The Gentleman's Magazine (London, 1747).