Opening Temple doors by fire on an altar, 1589.
© Science Museum / Science & Society Picture Library
Engraved diagram showing an alternative method of opening doors automatically. Heated air expands, and a system of chains, pulleys, and weights enables the doors to be opened automatically as long as a fire is burning. Illustration from 'Gli artifitiosi et curiosi moti spiritali di Herrone' (commonly called 'Pneumatics') by Hero of Alexandria, published in Ferrara in 1589.