First time I've seen this one:
I come back from the kitchen, and my reading lamp (spring-clamp lamp) is glowing dull orange.
Turn off the switch. Switch feels fine (not burned.) LAMP DOESN'T SHUT OFF! OK, so maybe the switch is fried.
Unplug the lamp. LAMP DOESN'T SHUT OFF! I have the power cord in my hand.
So, I guess the switch was OK after all?
Over about 15 seconds the orange glow fades to dark. Unscrew the bulb. It's hot, but not unusually so. It does operate base-upwards in the lamp.
Examine the inside of the lamp with laser-pointer shadow. The filament is fine, unbroken. But the glass support for the iron wires has a large hole melted in the side.
So, it was still an incandescent lamp, but it randomly decided to use liquid glass as it's light-generator? Rats, I should have plugged it back in to see how long it could continue that way.
((((((((((((((((((((((( ( ( (o) ) ) ))))))))))))))))))))))) William J. Beaty Research Engineer beaty a chem washington edu UW Chem Dept, Bagley Hall RM74 billb a eskimo com Box 351700, Seattle, WA 98195-1700 ph 3-6195