Prismatic lens

Giovanni Poleni bought this instrument for the Cabinet of Physics of Padua University between 1739 and 1742. He catalogued it in his Indice delle Macchine as “A crystal with several faces, i:e. a polyhedral crystal; by looking through it, one sees multiplied images. XI.2. Made by Domenico Selvi of Venezia”.

Maker: Domenico Selva, b.? - d.1758. Skilled and well-known Venetian maker of optical instruments, he had a workshop in San Marco.

Date: 2nd quarter 18th century


The instrument is made of a lens, whose surface is made of several small plane faces. The lens is inserted in a wood cone. By looking through the lens, one sees dozens of identical and slightly iridescent images. Poleni bought this instrument from Domenico Selva, a Venetian optical maker whose workshop was highly famed. It is worth reminding that, among the instruments Selva built and sold, several other instruments were related to what can be regarded as pre-cinematographic entertainment, as shown in the treatise Sei dialoghi ottici-teorico-pratici dedicati all'Eccellentissimo Senato da Lorenzo Selva, ottico pubblico stipendiato. The treatise was written in 1787 by Domenico Selva’s son, Lorenzo, who took up his father’s workshop. Part of the treatise actually deals with “Camera Obscuras, Prisms, Cylinders, and Cones”. Domenico Selva’s other son, Gian Maria, was one of Poleni’s pupils.

Materials and techniques: wood/glass

Dimensions: height 11 cm, diameter 11 cm

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

Keywords: optics, pre-cinema

University of Padua, Museum of the History of Physics

Cat. Number: 14


  • Jean-François Niceron, La Perspective curieuse, Paris, 1638
  • Jacques Ozanam, Récréations mathématiques et physiques. Contenant l'arithmétique et la géométrie, qui contiennent les problèmes & les questions les plus remarquables, & les plus propres à piquer la curiosité, tant des mathématiques que de la physique, Paris, 1694
  • Lorenzo Selva, Sei dialoghi ottici-teorico-pratici dedicati all'Eccellentissimo Senato da Lorenzo Selva, ottico pubblico stipendiato, Venice, 1787
  • Giovanni Poleni, Indice delle macchine, Biblioteca Nazionale Marciana di Venezia,, cl. III, 54-55 = 4969-4970, cl. IV, 626 = 5488, 636 = 5497 [It was written by Giovanni Poleni from 1740 to 1761]