Radioactive source for: Avo No 1 Mk 2 Radiac Survey Meter, by AVO Limited (formerly the Automatic Coil Winder and Electrical Equipment Company or ACWEECO), London, SW1, England, 1950-1969. Radioactive source for Radiac survey meter 1950-1969
Oscilloscope tube for detecting reverse current in induction coil discharge, part of x-ray installation, 1905-1909. Oscilloscope tube for detecting reverse current in induction coil discharge