Museo Galileo
Virtual Museum
Aurora tube
    • Setting:
      Room XI
    • Maker:
    • Date:
      late 18th cent.
    • Materials:
      mahogany, glass, brass
    • Dimensions:
      total height 580 mm
    • Inventory:
    • Aurora tube (Inv. 1203)

This device was used to simulate the aurora borealis phenomenon.

The glass tube is supported on a glass pillar, with a turned mahogany base, weighted by means of a lead ring to prevent the instrument from toppling over. A brass spike projects at right angles from the upper brass collar. A ball electrode is joined to the lower brass collar. Inside the tube are two other electrodes: the upper one ends in a point, the lower one in a ball.

The tube is partially evacuated by means of an air pump. The glass is then rubbed with a cloth or the electrodes are touched with the conductor of an electrical machine. The electrification causes the inside of the tube to glow with a light closely resembling an aurora borealis.

William Henley used a comparable instrument to demonstrate the glow produced by positive or negative discharges. He claimed this as proving Benjamin Franklin's theory of a single electric fluid. Filippo Lucci depicted a very similar device in the Stanzino of the Matematiche of the Uffizi in 1780—clear evidence of the popularity of such demonstrations in the late eighteenth century. Provenance: Lorraine collections.