12. The Keely Engine Took Investors on a Decades-Long Ride
Keely closely guarded the secrets of his invention for more than two decades, refusing to share its details with anybody. But he kept promising investors that the perfection of a commercial version of his machine was right around the corner. In the meantime, gullible investors kept giving him more and more money, notwithstanding the consensus of physicists that Keely was a quack and charlatan, and that perpetual motion such as he promised was physically impossible.
Finally, when Keely died in 1898, the secret of his engine was revealed to the world. It had not been powered by water, but by a compressed air machine hidden two floors beneath his workshop. The air compressor was connected to the Keely Engine by cleverly concealed pipes and hoses.