The genesys of the Royal Collection is strictly connected to the crowning of Charles  of Bourbon as King of Naples in 1734: shortly after he became king and by his will, the first “mathematical machines” were imported in the city; some of these instruments such as the telescopes’ objective lens by Evangelista Torricelli, a double burning lens by Brander & Hölscher and a gold and silver Sundial (1769) can be admired in the Physics Museum.

Under the reign of Ferdinand II, the collection was at the heigh of its splendor. It was enriched with modern instruments crafted by foreign makers: the magnetic compasses and the heliostat made in Paris by Gamby, the Atwood's machine, the Dollond's compound microscope and Chevalier's achromatic microscope are just a few examples of the magnificent tools created in that period. Following the Unification of Italy, part of the Royal Collection was incorporated in University of Naples’ Physics Cabinet and it is now exhibited in the Physics Museum.

Photo: Compound microscope given to Francis I of Bourbon by G.B. Amici, Modena 1825.

The Physics Cabinet of the University of Naples instituted in 1811 by Joachim Murat had a rather exiguous initial equipment: it essentially consisted of prisms, mirrors, optical illusion, and a few Camera Lucida built by Gaetano de Conciliis, first director of the Cabinet. Later on it was enriched with instruments and machines belonging to the Nunziatella Military College and some from private collections. Some new tools were acquired for the 7th Congress of Scientists held in Naples in 1845. In 1878, under the direction of Gilberto Govi, the Cabinet became a research laboratory equipped with some high-precision instruments such as the cathetometer, the dividing machine, the Deleuil scale and new electrical apparatus. Also the following directors were dedicated to the growth and the renewal of the collection so that by the beginning of the 20th century the Physics Cabinet counted about 1300 instruments.

Only half of this heritage has survived and is currently hosted in the Physics Museum.

Photo: Scales by Deleuil, Parigi, 1882.

In 1839 Ferdinand II of Bourbon designated Macedonio Melloni, physicist from Parma, as director of the nascent Vesuvius Observatory and the Conservatory of Arts and Crafts. Melloni’s fame was mainly linked to his experimental research on radiant heat. During his stay in Naples, he experimented with various instruments such as an optical bench built in Paris by Ruhmkorff, a portable optical bench and a thermomultiplier. In 1845 during the VII Congress of Scientists, Meloni demonstrated the calorific value of the Moon using a large Fresnel lens made in Paris by Henry Lapaute. He also invented a new kind of electroscope and entrusted its construction to the Neapolitan maker Saverio Gargiulo. The instrument was completed a year after Melloni’s death.

The Physics Museum currently houses Melloni’s instruments.

Photo: Melloni's optical bench, Ruhmkorf, Paris, first half of the 19th century.