It's missing one alligator lead, and a lightbulb (?). The transformers are both 24v. Is this a tester of some sort? I haven't plugged it in.
Thanks for your help.

 

It's a full wave rectified isolated power supply. The lamp holder is connected in series with the input to the two parallel connected transformer primaries. The two transformer secondaries are connected in parallel and are feeding the four selenium rectifiers connected as a bridge. The meter is for indicating current and is in series with the negative output. It is not a commercial product so I have no idea what it was built for

 

It's a full wave rectified isolated power supply. The lamp holder is connected in series with the input to the two parallel connected transformer primaries. The two transformer secondaries are connected in parallel and are feeding the four selenium rectifiers connected as a bridge. The meter is for indicating current and is in series with the negative output. It is not a commercial product so I have no idea what it was built for

Wow, thanks! It sure sounds like you know what your talking about, but I don't. It's a power supply? I think my great grandfather built it. Thanks for the info, I appreciate it!