Starting from the early years of the 18th century, the experimental results achieved by Isaac Newton (1642-1727) and published in Opticks became terms of reference for the Bolognese physicists engaged in the study of light and colours. Francesco Maria Zanotti (1692-1999) and his student Francesco Algarotti (1712-1764), in the early 1720s were the first in Bologna to perform crucial experimentation on the Newtonian theory of colours, i.e., the double refraction of sunlight through an optical prism.
Since 2003, the same room in Palazzo Poggi where the experiment was performed has been housing a statuary replica of the experiment inspired by G. Pittoni and D G Valeriani’s An Allegorical Monument to Sir Isaac Newton (Cambridge, Fitzwilliam Museum). The beam of light reflected by a mirror and refracted by a prism clearly shows the spectrum of colours comprised by sunlight.
In 1747 all the optical equipment made by Giusppe Campani (1635-1715), who had one of the most renowned workshops of the era, was placed at the institute’s disposal. It included finished lenses, bronze moulds to grind lenses and lathes to create the moulds. This finally made it possible to open a dioptrics laboratory, which had been requested by Marsili but never approved by the institute. The workshop was used both as a physics laboratory and to grind the magnifying instruments used at the observatory.
Action by Pope Benedict XIV also made it possible to purchase the equipment needed to set up a regularly held course in experimental physics, from Dutch artisans who had worked with van Musschenbroek and Gravesande.