On January 4, 1898, Elza J. Christie received a patent for his gyroscopic unicycle.
The unicycle was expected to reach speeds of up to 400 miles per hour. It seems it was never tested independently.
Patent Information
Publication number: US596480 A
Patent Title: Unicycle
Publication type: Grant
Publication date: 4 Jan 1898
Filing date: 26 Sep 1896
Publication number: US 596480 A, US 596480A, US-A-596480, US596480 A, US596480A
Inventors: Elza J. Christie