What is this "Radio Engineering Laboratories Wavemeter Cat. 125"?
I do not know the history of this device or where we got it from. The text on top has an "REL" logo (Radio Engineering Laboratories) and "WAVEMETER CAT. 125 SER. NO. 2041". There are three big coils on the compartment with different amounts of turns on them, and they mount to the screw things on the side. The awesomely cool knob goes from 0 to 100, but spins all the way around...it may have come loose inside. The lightbulb-looking thing has a standard Edison base, but isn't connected, just poked into the hole, I think the socket fell out. It looks like a neon lamp of some sort. There was also a laminated card in the box, a scan is attached.
What the heck is this thing? All Google came up with was a court case where someone sued REL in 1934.