National Institute of Standards and Technology Digital Collections, Information Services Division, Gaithersburg, MD 20899
The only thing really known about this medium-sized contraption is its dimensions and that it measured the luminosity of surfaces. The archives don't indicate the year this photometer was made, but the straggling electrical cord provides a decent hint.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.