Radioactive WW2 night vision test (1941)

> This is a night vision test developed and published by WD Wright in WWII. It relied on a radium light source (sadly no longer available) to provide a calibrated, low level of illumination.

So this is an equipment to test human vision in the dark, not related to EO “nightvision” technologies that the term more commonly refers to today.

The links at the bottom, unmangled:

http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC21617...

https://en.wikipedia.org/wiki/Isaac_Pitman

For those who aren't aware, radium paint was used quite a bit prior to the 1970s or so as a glow in the dark material, typically used on watches and clocks to allow them to be read in the dark.

You can still find many of these old items on ebay and in antique stores. Typically they no longer glow in the dark due to the radiation breaking down the phosphors in the paint, but they remain radioactive because the half-life is > 1000 years.

(I only know this stuff because of my interest in old tube electronics and radios, some of which have radium dial clocks)

https://en.m.wikipedia.org/wiki/Radium_dials