Although in non-working condition, this bulb is a very rare and collectible Westinghouse-Based, 19th century Sawyer-Man lightbulb. It is not worth a lot of money, since it is not in working order, but it is still a real 110+ year old bulb! I cannot afford Westinghouse-based bulbs in working condition because they go for too much in auctions. They usually sell for more than $70 USD (I'm sure many collectors out there hate me for revealing this to the public... Sorry guys!).
This bulb has a unique, Y-shaped stem and is insulated at the base with porcelain. I believe this stem design is a Sawyer-Man design. Bulbs insulated with plaster instead also exist, but these are even more costly to obtain, even if they don't work! Sockets
for this type of bulb are also very expensive. This bulb sports a squirted cellulose carbon filament, which looks very much like a black cotton thread when viewed up-close.
Westinghouse bases appear to be much larger in pictures than they really are. A person who has never seen one may think that they are as large as a mogul base, but they're not. Actually, they are the same size as a regular edison base (the common base type we still use today).
So, this is everything I know about this bulb, and as you can see, it's not much. If you know more about this bulb, please don't hesitate sending it to me.