Note 2 — Chapter I · Dawnings of Steam Power—The Marquis of Worcester.

The principle of the Æolipile is the same as that embodied in Avery and Ruthven’s engines for the production of rotary motion. “These engines,” says Bourne, “are more expensive in steam than ordinary engines, and travel at an inconvenient speed; but in other respects they are quite as effectual, and their construction is extremely simple and inexpensive.”