Radioluminescent Toggle Switch (ca. 1940s)
This toggle switch employs a radium-containing radioluminescent compound in the small glass ball at the tip of the switch. This radioluminescent material is white in color. My best guess is that the switch was employed on military aircraft.
The only marking that indicates the manufacturer is the "CH" on the upper front face of the switch plate. This refers to Cutler Hammer.
Also on the front is the statement: "Made in USA Patent 1605910." This patent turns out to have been issued in 1926 to Ernst Appleton and Ludwig Larsen of the Roach-Appleton Manufacturing Company of Chicago, Illinois. The company later became known as RACO and today it is part of Hubbell Electrical Products.
Gamma spectrometry measurements indicate a Ra-226 activity of 0.11 uCi. The exposure rate at 1 foot is approximately 2 uR/hr above background.