Giovanni Poleni bought this instrument for the Cabinet of Physics of Padua University between 1741 and 1742. He catalogued it in his Indice delle Macchine as “A fountain, made of two large cylinders, two tubes and a nozzle (called Heros’s fountain by some people ); by pouring water on one side, the fountain’s nozzle jets wine. It is useful to demonstrate the elastic force of air. It is all made of brass”.

Inventor: Hero of Alexandria, c. 10 – c. 70 d.C.

Date: 2nd quarter 18th century

Description

It is a variant of the classical Hero’s fountain, invented in the 1st century. The device consists of two containers communicating through a couple of tubes. When the upper vase was three-quarters full with liquid, more liquid was poured in the lateral funnel, which is directly connected to the lower container through one of the tubes. When the liquid arrived in the lower container, it compressed the contained air and expelled it towards the upper vase through the second tube. There, the arriving air compressed the liquid of the container and expelled it upwards, outside, through a very short tube. The liquid then gushed out above the instrument. Poleni used this instrument with two different liquids so that “by pouring water on one side, the fountain’s nozzle jetted wine” (Indice delle Machine).

Materials and techniques: brass

Dimensions: height 64 cm, diameter 23 cm

Related scholars: Giovanni Poleni (b.1683 - d.1761). Professor of Experimental Philosophy at the University of Padua from 1739 to 1761.

Keywords: mechanics, pneumatics

University of Padua, Museum of the History of Physics

Cat. Number: 31

Exhibitions

• "Bagliori nel vuoto. Dall'uovo elettrico ai raggi X: electricity e pneumatica dal Seicento ad oggi", Padua, Botanical garden, 1 February-30 June 2004

Bibliography

• Joseph Théophile Desaguliers, Cours de physique expérimentale, 2 vols., Paris, 1751
• Jean Antoine Nollet, Leçons de physique expérimentale, 6 vols., Paris, 1a ed., 1743-1764
• Adolphe Ganot, Traité élémentaire de physique expérimentale et appliquée et de météorologie, 14 ed., Paris, 1870
• Giovanni Poleni, Indice delle macchine, Biblioteca Nazionale Marciana di Venezia, mss.it., cl. III, 54-55 = 4969-4970, cl. IV, 626 = 5488, 636 = 5497 [It was written by Giovanni Poleni from 1740 to 1761]