French scientist and balloonist Gaston Tissandier published this image of a "swimming apparatus" in his book Les Récréations Scientifiques in 1883. The book is full of similarly amusing illustrations of his ideas, experiments and inventions. I wish I could take a ride on this swimming apparatus. I love that it has a propeller.
From the PDR: "If the experience of wonder can lead to either a suspension of rational thought or toward a form of curiosity that fuels the search for knowledge, it is, without question, the second path that French scientist and balloonist Gaston Tissandier espouses in his Les Récréations Scientifiques. This comprehensive, 800-page textbook covers everything from the basic laws of motion and spectroscopy to botany and new forms of transit. Throughout, Tissandier weaves personal anecdotes and DIY experiments together with explanations of natural phenomena to infuse pleasure and amusement into the process of scientific learning."
See also: Deeply satisfying video of guy scraping gunk off a lobster boat