Left: an aeolipile (right) shown connected or coupled to a weight (left) in the form of a heat engine, to demonstrate the heat conversion into work aspect of the mechanical equivalent of heat. Right: a modern laboratory scale aeolipile.
In engines, aeolipile, aka "ball of Aeolis", is a device in which steam contained in a boiler is release through oppositely facing orifices of a hinged bulb causing rotation of the bulb.
Overview In 250BC, Greek compressed air engineer Ctesibius is attributed to have invented the steam spinning device; which is often assigned as being the world's first prototype steam engine:
These came to be known as the ‘aeolipile’ as described by both Roman architect Vitruvius (15BC) and Greek physicist Hero (50AD). [1] Owing to the fact that Hero was the first to give a detailed account on how to make an aeolipile, the device has since come to be known as Hero's engine or the aeolipile of Hero.
