How to ID strange capacitor?


Sorry for off topic, but I don't yet know where this is on topic.

I found a box of capacitors from around the 1950's yesterday in a barn. I hope to identify them if possible. Who would know? Where should I ask? Hmmm.

They are built like tanks. (judging by the other gear in the room they could have been in a tank, lots of US Army Signal Corps stuff)

They are .75" round by 2" long, weigh about 1/4 pound, are .47 microfarad - 600V axials and have a very beefy porcelain tube encapsulating them. They say "type 177" and have a logo that looks like a "G" with an "I" sitting where the crossbar of the G would be. Oddly they test within specs and seem to work nicely after 1/2 century.
Thomas


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