Aeolipile

A round vessel caused to rotate by the force of tangentially escaping steam: an early example of jet propulsion.

It consists of a hollow metallic ball which rotates about its vertical axis, with horizontal arm-like tubes projecting radially, and having their free ends bent round in a tangential direction. When the water in the globe is heated, and steam rushes out of the tubes, rotation is established. The aeolipile was invented in 120 BC.