The cups were bought by Giovanni Poleni for the Cabinet of Physics of Padua University between 4 September 1743 and 2 February 1745.

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

Maker: Galli brothers, active in Como.

Date: 2nd quarter 18th century

Description

Tantalus’ cups, designed by Hero of Alexandria in the 1st century, became classical elements of 18th- and 19th-century cabinets of physics. They provided a spectacular demonstration of the action of syphons and atmospheric pressure. A syphon is actually inserted within the cups, so that when some liquid is poured in, nothing happens at first but, as soon as the cups are almost full, the liquid starts escaping from the little spouts underneath. Two cups have survived from the three that were originally bought by Giovanni Poleni. The latter used wine instead of water, in order to enhance the spectacularity of the experiment. He described these devices in his Indice delle Macchine as “Three glasses with their glass syphons. In these glasses, the wine stays as long as they are almost full but, when they are full, all the wine escapes. This experiment illustrates the theory of suctions.”

Materials and techniques: glass

Dimensions: height 20 cm, diameter 10 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: 47

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

• Erone di Alessandria, Spiritali di Herone Alessandrino ridotti in lingua Volgare, Urbino, 1592
• 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]