I bought a lightbulb (and a ceramic holder and rotary lightswitch) in a second-hand shop yesterday. They had many beautiful items taken from an old electronics teaching laboratory - all brass, steel, ceramic and wood.
The lightbulb: .
It's about 10cm tall, and has an Edison screw. The filament loops up and down the bulb in six lengths. It's made by Osram, but there are o other readable markings on it.
Any idea what the purpose of a lightbulb like this might be?
I'm tempted to run it at low voltage to see what it looks like illuminated, but I'd hate to damage the filament.
Daniele