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Cathode Ray Tube with Two Minerals

A glass instrument on a turned wooden base. The wooden base is light yellow-brown in colour and has a glossy finish. The glass component consists of two pillars joined by a horizontal tube-like connection near their base. A stem at the centre of this connection joins the glass component to the wooden base.

Near their tops, each stem widens into a hemispherical shape. At the centre of both hemispheres, an inner stem terminates in a mineral held in place by glass. At the very top of each stem is a circular metal element terminating in a conductive cap.  

Accession Number:

Alternative Name:

Primary Materials: Wood, Glass.


Dimensions (cm): Height = 42, Width = 23, Length= 14.



This artifact is in excellent cosmetic condition and appears undamaged.

Associated Instruments:

Manufacturer: Unknown

Date of Manufacture: Early to mid 20th c.


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
This artifact was accessioned as “PHY 29” on January 16, 1978

Historical Notes: