Useful for the relation betwen wattage, area, and time to be an effective germicide and virucide
Provides numerical figures showing wavelength effectiveness
Author of Instruments of Amplification, H. P. Friedrichs outlines his exploration into growing cuprous oxide on copper
to form a "primitive radio detector" as he calls it -- or in the words of Grondahl (the original US Patent 1,640,335 author),
a "Unidirectional Current Carrying Device". In common terminology it can be called a diode!