[Phlogiston]

I posted a video on my blog of a gassy 280 that is so gassy that it forms an ion cloud as I switch from side to side (plate to plate). This is also a great demonstration for a beginning radio fixer of what gas looks like in a tube. I do this for my own entertainment (yeah it does not take much) and it usually takes up to 7 or 8V on the filament of a gassy rectifier to get it to conduct at all. The purple glow is usually contained within the plate structure.

For your amusement:

http://www.russoldradios.com/blog