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Cathode Ray Tube with Four Minerals


A four-mineral fluorescing cathode ray tube. A black turned wooden base with a metal plate attached to the bottom and a glass tube, approximately 27cm in length, with 2.5cm projection from the side, mounted on top. A projecting glass tube contains the base of a metal ring which extends around the inside wall of the main glass tube. On the top of the main glass tube there is an electrode. Four different minerals are supported on small glass arms in the centre of the main glass tube.

Accession Number:

Alternative Name: Crookes Tube with Four Minerals

Primary Materials: Wood, Metal, Glass

Markings: Old Inventory Number = phy78.

Dimensions (cm): Height = 33, Diameter = 7.5


Minerals are fluoresced under the bombardment of cathode rays. Possibly used for spectroscopy.


Associated Instruments:


Date of Manufacture:

Provenance: Collection of Dr. Martin Lee.

Additional Information and References:

In October 1898, instructor and future professor J.C. McLennan visited the Geissler Establishment, in Bonn, Germany. The Geisslers were famous for the manufacture of Crookes Tubes. McLennan reported in a letter back to Professor James Loudon that he had purchased some of these for the Toronto physics laboratory, including at least one with a “phosphorescent mineral”, which, he reported, “gives the most beautiful effect that I have seen.” (McLennan, 1898)

There are numerous examples of phosphorescent mineral tubes in the collection. It is possible that one, or more, of these were purchased by McLennan during his 1898 trip to Bonn.

Letter from J.C. McLennan to J. Loudon, October 10, 1898. University of Toronto Archives B1972-0031 Box 004 File 43

Historical Notes: