A 20 cm glass bulb with two 3 cm projections on opposite sides. The glass bulb contains three electrodes. A 6 cm tube is mounted inside the large bulb. The bulb is supported by a metal collar, supported by twin metal rods emerging from a turned wooden base. The side of the bulb near the collar reads “861” and a large capital ‘G’, with a set of scales in the middle of the ‘G’.
Accession Number: 2009.ph.26
Alternative Name: Crookes tube
Primary Materials: Wood, Metal, Glass
Markings: Old inventory number = phy68.
Height = 35, Base Diameter = 13, Bulb Diameter = 20
When a current is applied, the thin strip in the middle of this tube (likely platinum coated with calcium oxide) acts as a cathode without an external anode. According to it’s catalogue, this device was used to demonstrate the circular bending of cathode rays in a magnetic field and to determine the relationship between the charge and the mass of an electron.
Date of Manufacture:
Additional Information and References:
Likely made by German manufacturers Richard Muller-Uri and Max Kohl.