Information on Vintage Bulb

[k7jsm]

I wonder if someone would help me determine what the history of this fixture
might have been. 

Thanks much!

[Tim]

Welcome to the forum.  This isn't a light bulb, but rather an early Geissler tube used to demonstrate the properties of gaseous glow electrical discharges.  These tubes were made for both show and scientific demonstration beginning in the 1800s.  Most were made by Pressler in Germany.  I'm not an expert on Geissler tubes but I'm certain you're tube is fairly early (1890s-1900 perhaps) judging from the look and shape of the electrical terminals.  Outside of the this, these tubes can be difficult to date.  The tubes were originally made to be lit by induction coils.  Today, an old Model T spark coil will work as well as the old high frequency violet ray wands (touching the wand to one terminal).  Never use a neon transformer on one of these tubes - you will easily destroy it.

Here's a link showing some of my tubes lit:

http://bulbcollector.com/gateway/Vacuum_Tubes/Crookes_and_Geissler_Tubes

[k7jsm]

Thank you for the information.  Do you have any idea where an item such as this would be best to sell?  Any
idea what type of value it might be worth?  Thanks a lot for your assistance.  You have a completely cool web
site for this.

[Tim]

eBay is probably the best outlet.  Values are typically driven by the size and complexity of the tube, and of course knowing if the tube still works.  It's not uncommon for these tubes to loose their vacuum, thus rendering them unusable.  I haven't looked at the values of Geissler tubes in many years but I would try and verify the working condition of your tube and list it with a reserve of around $75 or so assuming it still produces a glow.  Photographing the tube lit will surely help an auction description grab the attention of more bidders too.  It's a good idea to also research past auction sales - just search eBay's completed auctions for the keyword "geissler" or "crookes" to get a feel of values.