Radioluminescent Gauge (ca. 1950s, 1960s)
|As the label on the
side indicates, this voltmeter employs a radioluminescent meter face. I
assume that it was produced in the 1950s or 1960s because the radiation warning
symbol was developed in the late 1940s, and because the use of radium
(Ra-226) decreased dramatically after the 1960s. It was manufactured
by Wacline, Inc., of Dayton Ohio. The Ra-226 content
is probably 0.5 to 1.0 uCi. In this example, the radioluminescent paint,
which has a light tan color, is applied to "A.C. VOLTS," the
numbers 0 through 150, their associated hash marks, and the tip of the
Radium-containing radioluminescent gauges have been around at least since World War I when they were employed in aircraft.
S.A. Sochocky. Can't You Find the Keyhole? The American Magazine Vol. 91, Jan.-June, 1921.
Copyright 1999, Oak Ridge Associated Universities