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Gassiot's Cascade I’ve been wanting to reproduce this for some time and finally managed today, although I need to perfect the look a bit. The experiment was first shown by Gassiot in the 1850s. If done correctly it should appear like a plasma ‘waterfall’ cascading over a jug. The jug was made of uranium glass so as to fluoresce with the UV content in the air discharge. I have a uranium glass bowl inside my vacuum bell-jar; the pressure is not quite correct for the effect but I also don’t want to stress my feed through connector or the discharge may break down the epoxy resin I’m insulating it with. The vacuum pressure here is around 3 Torr. The voltage applied is around 900V DC with the thin wire in the bowl being +ve and the metal base -ve. There were some rare complex Geissler tubes made which incorporated a miniature uranium glass vessels to permanently display this arrangement. Keywords: Miscellaneous

Gassiot's Cascade


I’ve been wanting to reproduce this for some time and finally managed today, although I need to perfect the look a bit. The experiment was first shown by Gassiot in the 1850s. If done correctly it should appear like a plasma ‘waterfall’ cascading over a jug. The jug was made of uranium glass so as to fluoresce with the UV content in the air discharge. I have a uranium glass bowl inside my vacuum bell-jar; the pressure is not quite correct for the effect but I also don’t want to stress my feed through connector or the discharge may break down the epoxy resin I’m insulating it with. The vacuum pressure here is around 3 Torr. The voltage applied is around 900V DC with the thin wire in the bowl being +ve and the metal base -ve. There were some rare complex Geissler tubes made which incorporated a miniature uranium glass vessels to permanently display this arrangement.

Gassiot_Cascade.jpg pressure_tubes.jpg Geissler2a.jpg neon_question2_copy.jpg railtube.jpg
Lamp/Fixture Information
Manufacturer:home made
File information
Filename:Gassiot_Cascade.jpg
Album name:Tuopeek / Misc
Keywords:Miscellaneous
Filesize:550 KiB
Date added:06 Apr 2026
Dimensions:2500 x 2301 pixels
Displayed:22 times
DateTime Original:2026:04:06 20:07:46
Exposure Time:1/25 sec
FNumber:f/4
File Source:Digital Still Camera
Flash:No Flash
Focal length:27 mm
ISO:12800
Model:NIKON D3400
Software:Adobe Photoshop Elements 2.0
White Balance:0
URL:https://trad-lighting.net/gallery/displayimage.php?pid=1188
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Comment 1 to 13 of 13
Page: 1

Max   [Mon 06 Apr 2026 at 22:08]
Very nice demo there! I really like how the light from the discharge combines with the fluorescence of the uranium glass to result in white light emission. You have quite a large Faraday dark space there for a 3 Torr environment though... do you have a continuous gas feed to regulate the inner pressure, or is that a static gas volume? If it's the latter case, then it's possible that plasma gettering has actually reduced the operating pressure. You could also work at a slightly higher pressure in order to extend the positive column a bit beyond the cup, to form a "fluid" falling from it.
Sammi   [Mon 06 Apr 2026 at 22:08]
Oh wow.! I just love seeing things like this.! Love Mind Blown
Ria   [Mon 06 Apr 2026 at 22:46]
Indeed, we're lucky to have you both here Love
Max   [Tue 07 Apr 2026 at 10:56]
Thank you ladies, you're too kind!
Tuopeek   [Tue 07 Apr 2026 at 12:17]
@Ria Good to be here too. Very Happy

@Max I'm know wondering if this picture related to 3 Torr. I took a few images between 2 and 4 Torr. It is a static volume although. I was considering back filling it with some welding argon to see how that looked. Welding gas tends to be a bit contaminated for discharge work though. I will have another go with this as I have left it set-up to play with. I do expect my epoxy insulated feed-through to fail if I get close to 3kV or maybe even less in the Paschen-minimum environment. So that's another thing to improve. Vacuum parts and feed-throughs are expensive but I'm sure something can be made cheaply that will work for the experiment. Very Happy
Eric   [Tue 07 Apr 2026 at 19:14]
Nice display! Wish I had the space and time to be the "mad scientist".
Yes, many thanks to Ria and Sammi for allowing us LG exiles a place to gather. Cool
Tuopeek   [Tue 07 Apr 2026 at 22:26]
Thanks Eric, Wish I had more space to be even madder but my wife and the neighbours complain as it is Laughing
Eric   [Tue 07 Apr 2026 at 23:54]
Yeah, I know how that goes... Rolling Eyes
Ria   [Wed 08 Apr 2026 at 00:23]
Heh. My wife just adds to the madness Rolling Eyes Mr. Green
Sammi   [Wed 08 Apr 2026 at 00:31]
I do my best... Laughing
Max   [Wed 08 Apr 2026 at 06:08]
When it comes to those experiments, the madder the better! Laughing
Maxim   [Wed 08 Apr 2026 at 22:41]
This is quite impressive, Tuopeek. Not only the experiment itself, but also your presentation and photography. Very nice work.
Tuopeek   [Fri 10 Apr 2026 at 15:39]
Thanks Maxim, Now I have this set up I am tempted to try lots of different effects in the chamber and take pictures. Some images can be very atmospheric with blue plasma hazes like mist or wavy lines.

Comment 1 to 13 of 13
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