I'm trying to determine if all the parts are there. The labels pasted inside the shade say "do not operate without complete bulb enclosure in place or if lens is damaged." I can't find a "lens" unless that means the frosted dome atop the shade. There's what looks like an aluminum "doughnut" that holds the J-type socket and bulb, and a wire grid that shields the bulb. But there are also two little metal clips affixed to the doughnut, just below the socket terminals, that don't seem to have a function unless it's to hold the missing lens.

Also there's no on/off switch. Maybe you are meant to plug/unplug it every time.

Does anyone have ideas? It would be neat to get this working again.

I will try to post a picture as well. Many thanks.

They are both very hot (the 'glass' is actually quartz), produce some UV, and can failure with a decent explosion of hot glass white hot tungsten from the filament.

Plastic is rarely suitable as a cover .