The creators of "perpetual" engines were not only adventurers, ordinary "homemade" - naturalists and visionaries. History knows several examples of how rather prominent scientists, creators of quite real and useful mechanisms, were carried away by the idea of perpetuum mobile.
The Frenchman Denis Papin is one of such scientists. Papen was engaged in physics and mathematics, as well as invention. Although fate prepared for him the fate of becoming a doctor (Denis Papen studied medicine at the University of Angers and received his doctorate), a meeting with the Dutch physicist and mathematician H. Huygens changed Papen's views.
And quite dramatically, although Papen's first inventions were a failure. In 1685, an article appeared in the journal Philosophical Works, in which Denis Papin proposed for consideration a project of a "perpetual" engine using the hydraulic principle of operation (while allegedly "refuting" the hydrostatic paradox).
The device of the "engine" was a vessel that narrowed downwards and passed into a thin tube, and the tube, bending like a wheel, hung over the “bowl” of the vessel. Papen believed that as soon as the vessel was filled with liquid, the latter, due to the pressure difference in the wide bowl and the narrow tube, would squeeze the liquid out of the thin tube. Just substitute the water wheel under it, and use the resulting power!
Of course (and any modern high school student will confirm), obeying the law of communicating vessels, the liquid simply froze at the same level in a wide bowl and a narrow tube: after all, the pressure was the same there and there.
The steam boiler invented by Papen.
The strangest thing in this whole story was not even that the fallacy of such an "engine" was obvious even for the science of that time, and not that it was not so difficult to assemble and check the operation of the device, but that Denis Papin (to all already in the position of a temporary curator of experiments at the Royal Society of London) for some reason sent an unverified project to a scientific (for its time, of course) journal, and he published it. Such is the unusual scientific paradox!
A funny video of experiments with Denis Papen's GVD (Budweiser!:)):
Promotional video:
It is good that on a strange publication Denis Papin's experiments with a "perpetual" hydraulic motor ended and, changing the direction of research, Papen in 1690 creates one of the first steam boilers. And then he invents many more extremely useful things: a safety valve for his steam boiler, a centrifugal pump, creates projects for a steam carriage and a submarine, makes the first pressure cooker …
