Date: 4th quarter 19th century

Description

The tube consists in an egg-shaped vessel mounted on a wooden support. A lead ring is inserted in the wood under the support, to make the instrument more stable. One of the electrodes, fixed at the top of the tube, terminates in an aluminum disc, while the other electrode terminates in a tip and is fixed on one side of the tube, close to the base. A glass column, inserted in the basis of the tube and ending at the center of the tube, supports a mineral, which glows when an electrical discharge is applied.

Crookes showed that, among the substances he had studied, diamond was the most sensitive in producing a quick and bright fluorescence. Ruby was also remarkable in this sense: it shone “with a brilliant rich red tone” (Crookes, 1879).  

Materials and techniques: glass/wood/lead/aluminum/mineral

Dimensions: height 41 cm, diameter 14 cm

Keywords: electricity, modern physics

University of Padua, Museum of the History of Physics

Cat. Number: 831

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

• William Crookes, On Radiant Matter – A Lecture delivered to the British Association at Sheffield, August 22, 1879, “Nature”, vol. 20, 1879, pp. 419-423 e pp. 436-440
• C. Gerhardt, Preis-Verzeichnis über Physikalische Apparate, Instrumente und Gerätschaften, Bonn, 1902
• J.E.H Gordon, A Physical Treatise on Electricity and Magnetism, 2 vols., London, 1880
• Max Kohl , Catalogue n° 100 - Installation des Salles de cours, Appareils de physique, 3 vols., Chemnitz, 1927