Radi-Glo "Spotter" Button (ca. 1940s)
This Radi-Glo "Spotter" Button was produced by Lustrolite Cleveland Corporation of Cleveland, Ohio. It might have been manufactured during the 1930s, 1940s, or 1950s. Its hard to tell. The only thing that helps date it is a reference to "Scotch" tape which was invented in 1930.
The button is approximately 0.5" in diameter. The radioluminescent material, ca. 0.3 uCi of Ra-226 mixed with zinc sulfide, is distributed in a ring around a central hole. The latter is counter-sunk so that the button can be held by one of the screws holding the plate of a wall-mounted light switch.
The back of the card describes "Some of the hundreds of uses for Radi-Glo Spotter Buttons." These include marking hazardous obstructions, doorknobs, keyholes, flashlights, auditorium seats, telephones and fishing lures. Some of the less utilitarian recommendations include using the buttons as decorations on dresses, and hair ribbons.
Donated by William Kolb.