Heros Engine

Hero's Engine, made first by the ancient philosopher of that name, is a steam-engine working on the principle of Barker's mill (q.v.), but forcing steam out of lateral jets in the vessel instead of water. The momentum of the issuing steam causes a retrograde rotation of the vessel which is pivoted so as to move with freedom.

Hero's Fountain is a contrivance for forcing a small jet of water into the air by means of compressed air, the compression being produced by a difference of water-level.