I record public domain audiobooks of works that are out of copyright for the website Librivox. My most recent project is a section of John Phin’s The Seven Follies of Science, a collection of bogus inventions, ideas, etc. based on seven impossible “scientific” ideas. Although Phin is most famous as a theist, this book shows that he was very well versed in science and mathematics. For something written in 1906, the modern scientist will find it quite readable.
My section in particular deals with perpetual motion machines. Phin divides these up in a section on “absurd” devices into a few core classes:
I. “Directed Momentum” Machines
These machines use weights placed at strategic positions, either in channels or attached via rope or rigid rods, around a central spinning wheel. The (fallacious) idea is that the weights will counterbalance one another perfectly to prevent the wheel from slowing down or stopping. See below for a few examples from the book.
II. “Hydraulic” Machines
The idea of these machines is that the weight of water in a large container has the ability to push a smaller, deeper quantity of water through a connected tube and back into the top of the container. This is physically impossible because the water in the large container can only exert enough force to push deeper water to its own level—no higher.
III. Liquid Conveyors
The most interesting of these uses an Archimedean screw to convey water upwards, which falls back down to power the screw. It’s not tough to see that the force of the falling water will not be sufficient to turn the screw, despite the drawing below. Phin debunks a similar idea that employed mercury in place of water (because, you know, mercury doesn’t stick to stuff).
IV. Capillary Action Machines
Interesting idea here—can capillary action result in perpetual motion? Unfortunately the answer is decidedly no; however, Sir William Congreve of Congreve rocket fame did his damnedest to build such a machine (and before Congreve, even Robert Boyle speculated about the possibility of such a machine). The machine looks creepily like tank treads!
V. Magnetic Machines
It’s invisible, it’s funky…and a lot of people believed it could facilitate perpetual motion. However, machines incorporating magnets, such as the one below, are also shown bogus.