The Turn Of The Century Electrotherapy Museum
(C) Jeff Behary 2010 

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Experimental Tesla Phosphorescent Bulbs II

Half painted black to better see phenomena

A very bright phosphorescence of glass.  Note the bluish phosphorescence of the hard glass stem compared to the green phosphorescence of the softer soda glass bulb.

Heavy electrification of bulb.  Filament occasionally lights, but requires precise placement in the bulb for efficiency.  (See Tesla lectures)

Slight reddening of filament.  See ends of broken filament forming "star burst" patterns inside the bulb.

This is quite striking in appearance!

Even on the non-painted bulb you can see heavy electrification.  

See also bits of projected filament hitting the glass walls (to the left)

Incadescent spots appear where filaments hit the glass walls.  This eventually leads to punctures of the bulb.

The bulb to the right has a higher vacuum, backing up a spark nearly the height of the bulb.

Here the only remaining filaments are at the wires leading out of the stem.

Vacuum begins to change, likely due to a pin hole puncture.  This may or may not repair itself, it depends on how pliable the glass was at the point of contact!
During one stage the vacuum was lower and then immediately became higher, showing a "self-repair" of the bulb.  This was outlined in Tesla's 1897 lecture published
by the great Leland Andersen.


(C) Jeff Behary, 2010