Even More Unidentified Objects... Sub-miniature tubes?

I can't seem to help myself... Someone tries to throw something away that looks interesting and I end up with it in the back of my truck. My garage is chock full o' stuff like this...

Are those things sub-miniature tubes?
They aren't marked in any way...
My background is in solid state, but I'm trying to learn and experiment with tubes now.



Or there's a bigger image at:
http://northsiderap.com/DIY/X3.jpg

Thanks to all the wizards out there who are helping me along...

Most likely they are "NE2" neon bulbs. Two electrodes in a neon atmosphere. Nothing happens until a breakdown voltage is reached around 70-90V, then the gas ionizes and the impedance between the electrodes drops a lot and current flows. A certain minimum current is required to sustain the discharge. They were used extensively as indicator lamps in the old days and still show up in plugstrips etc.

My first "aha" with electronics was when I built a relaxation oscillator with an NE2, a resistor, a cap, and a 90V battery. I went on to make a metronome with one at the heart and a tube relay driver to generate the click. It had a bit of jitter and was eventually rejected by my music teacher. Those were fun days, even accounting for selective nostalgia.

The bigger gas bottles, such as the OD3, can be used as shunt regulator elements for voltage regulation, although zener diodes are now usually the device of choice.