old light bulb

[Celt]

I posted about this *over there* in tubes...so I guess I'll stick it in old radios over here.
My house was built in the '40s and this is the only original fixture left in it. I think the bulb is original to it,
but some say it's a reproduction bulb. All I know is that I've been here since '89 and it was here when I arrived!
The base is etched "60W - U.S.A." and the top has nipple like you see on 9 pin tubes.