Lister Genset whutizit

The part shown is from the control panel of my 1915 Lister Bruton Genset. It is connected in the charging cicuit. What is it? The two pins are spring loaded and the brass base near the porcelain is threaded to accept the missing part. Since there are already two standard bulb sockets and three standard toggle switches, I'm halfway certain it is neither of those. I'm leaning toward some sort af fuse device, but have never seen anything like this. Has anybody ever seen anything like this?

For want of a better description, it's a terminal strip. Since I don't know where it's connected, it may be for a fuse, or it may be a take off point. You should have a small hole in the side of the spring loaded things that you can insert a wire into when the button is pushed. When you release the buton, it holds the wire with spring tension.

Franz, Close, but no cigar. There are no holes to put a wire into. I originally thought it might be a power point, but it is wired thruogh what I think was an electromagnetic coil, whatever it is, the screw base below the porcelain is key to the puzzle. Probably a fuse. What I'm hoping is that someone will reinforce my thinking, or might recognize the part in question. Part two of my problem is that there is another part missing from the control panel, which I think was an electromagnetic coil.
GUS

I seem to recall seeing something very similar at the bottom of old light sockets. The two posts look like they might be spring loaded inside. Will have to go back and check.

Hi Gus,

It's the bottom part of an old U.K. type BAYONET light bulb socket. There should be a brass sleeve on the top with two cutouts to take the retaining pins of the bulb, and a milled ring with a thread inside to hold the two parts together. If you need a picture email me and i'll find one to photograph for you.

Graham.