RARE Antique Ingersoll Radiolite Radium Lamp Socket Pull Chain

Description

This auction is for what I believe is a really RARE radium-infused pull chain for early lamp sockets.  As the ads that found on the internet suggest, these glowed in the dark so that they could be seen at night.
This one is kind of weak, but when exposed to a blacklight does glow pretty well.
The bottom glass part (which is all that really matters) on this one has an unusual cone shape and is 1/2" long.  The rest of the chain is 13" long.
The Ingersoll company is primarily known for making glow-in-the-dark watch dials, but apparently also made a few pull chain lamp pulls as well.  I only see these offered occasionally and they are really hard to come by.  I have included a few ads that I found on the internet for examples of these when when they were sold.  In addition, here is a readily available link to a description in Hardware Dealer's Magazine about these.  Copy and past this link into your browser or simply search Ingersoll Radiolite Socket on G
oogle.
books.google.com/books?id=b5o7AQAAMAAJ&pg=PA520&dq=ingersoll+radiolite+socket&hl=en&sa=X&ei=J-WdVMiXKoLqggTXxYC4Cw&ved=0CDoQ6AEwAg#v=onepage&q=ingersoll%20radiolite%20socket&f=false
I am asking what I believe to be a very fair price for this really rare item but I will still consider fair offers.
Thanks for your interest, and please see my other listings for more lamp parts.