Lrg One Wheel Tractor
One wheeled homemade tractor from Popular Science 1933 –

With a power plant that is suspended securely inside of a big ring-shaped wheel, a garden tractor has been built largely from odds and ends by R. D. Read of Akron, Ohio. It operates like the unicycle automobile developed in England. (P.S.M. May, ’32, p. 63.) A single-cylinder motorcycle engine was used without modification except for the installation of an additional gear for cranking, and a planetary type clutch operated from the plow handle.

Modern Mechanix » Homemade Tractor Has One Wheel – Link.