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

Date: 2nd quarter 18th century

Description

These six paintings, which were originally accompanied by three prisms covered with mirrors, were intended to study the reflection of light on plane mirrors. Poleni described his apparatus as “Three prisms […] And a painting about fourteen inches long with three figures. And six cardboards with various small figures. They serve to show how the position of figures change in mirrors: in catoptrics experiments to explain the reflection of pictures. XXXI.4.a.b.c.d.e.f.g.h.i.k.” (Indice delle macchine)
For the demonstration, the prisms were placed on the cardboards and one observed the angle formed by the two mirrors: the figures that were represented in different places on the cardboard appeared gathered and united. The place for the prismatic mirrors is marked by a pencil sign on the first cardboard, while it is marked by small pasted cardboard strips on the others.
The figures on the cardboards are: 1- Three men drinking and eating. They are represented on a sheet of paper pasted on a wooden board. The painting looks more sophisticated with respect to the others, and it could correspond to the “fourteen inches long with three figures” described by Poleni (Indice delle macchine). 2- A woman with a bird and a cage: the woman is at the center, the cage on the left and the bird on the right. There were two possible positions for the mirror, and one could either see the woman holding the cage, or the bird close to the cage. 3- A vase and a tree, respectively on two sides of the cardboard. The mark for the mirror is at the center. The reconstructed picture shows the tree in the vase. Two small pieces of papers are pasted close to the paintings, each one with an ink drawing representing one half of a vase. The vase is recomposed thanks to the mirror. 4- A man and a cart. In the mirror, one sees the man pushing the cart. The place for the mirror is at the center. 5- The bust of a woman on the left and a window on the right. The recomposed image shows the woman looking out the window. Two small pieces of papers are pasted close to the paintings, each one with an ink drawing representing one half of a human bust. The bust is recomposed thanks to the mirror. 6- A basket on the right and a bread on the left. By looking at the mirror, one could see the bread in the basket.
The Museum of the History of Physics owns also the cardboards that were used to prepare the strips marking the place of the mirrors. This suggests that the cardboards were made or transformed at the University. As for the small ink drawings, they seem to have been added later, probably to have more figures without preparing more cardboards.

Materials and techniques: cardboard

Dimensions: width 34,5 cm, length 14 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: 53

Bibliography

• 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]