mystery radio parts

[jbivy]

I picked up a jumble of old radio parts on ebay. Theres two items i cant identify. One is an old breadboard style bakelite tube socket made by Federal. Its for a four pin tube, but for one less than an inch wide at the base.

The other thing is an aluminum square, with a circle design on one side with a terminal in the middle. The other side has several holes and a terminal hookup in the center of that. Its made to unscrew in seconds, on the inside its just two cotton? O-gaskets with what looks like iron filings in between then. I recall some early radio receivers that used iron filings, could this be a form of coherer? Its made by "universal" with patent pending on it.

I'll try to get pics up soon.