The "Human Gyroscope" is no longer a part of the modern circus repertoire, but in 1909, the gyroscope represented the pinnacle of technology, serving as the heart of torpedo guidance systems and ship-borne navigation systems. And then, as now, the most advanced technology was often put to the silliest uses.
Popular Mechanics called the pivoting Frenchman "one of the most thrilling acts now being staged," though the article reveals, as this vintage advertisement does not, that Monsieur Menn-Ret was tethered to a rope throughout the act. But the rope held him up only until he could pedal his flying-saucer-like gyroscope up to speed. Once the disk was spinning rapidly enough, the rope was slackened, and the disk's angular momentum kept the Human Gyroscope from flopping off the side of the pole.