Geissler Tubes - Periodic Table of Videos

[@FishPit]

Would love to hear more about your grandfather in future videos. Sounds like he was an amazing guy.

[@happilicious]

James Noble wow, saw u on Clive's channel moments ago

[@FishPit]

What can I say, I'm more fond of learning since I left school 10 years ago. Haha.

[@hyperkubus]

I think that is true for most people watching bradys videos

[@moritzkockritz5710]

There is an extra video on the Nottingham science channel, if you click on the i in the top right

[@vampyricon7026]

+

[@oldwolf9403]

This particular set of Geissler tubes appears to be from the 1870s to 1880s. They could be as late as the 1890s. Usually they included d asmall amount of mercury vapour, and uranium oxide in the glass. The internal tubes are usually quartz glass, the liquids can be any number of liquids from quinine to various alanines. The electrodes were usually made of platinum. The styles shown here are generally found in French manufacture, and may contain rhodamine (for red fluorescence) quinine, for blue, or various combinations thereof. Some were engineered to deliberately show stratification in the plasma with distinctive banding (dependent on internal leakage), others contained powders to recharge or reduce the pressure, and absorb contaminants. There was a run of production int he 30s as well, if I remember correctly, but these appear to potentially be quite a bit older. The most unusual geissler tubes were actually mechanical/physical electrical valves, which would divert the energy to one side of the tube or the other, dependent on the electrical 'flow' direction, using the formation of the glass itself to make the rectifying effect. The ones with red glass in the sealing surfaces (around the electrodes) are probably pre-1900.

[@superchuck3259]

Interesting you mentioned electrical flow as his father was working on circuits. Also back then vacuum tubes are common and today replaced with ICs.

[@joshuarosen6242]

You clearly know what you are talking about and thank you for that informative post. I am curious to know how someone learns about something that seems, at least to me, to be so obscure. How did you become interested in Geissler tubes?

[@lapeez2277]

ooo uranium glass. pretty cool. stopped making it except in some place in switzerland i think

[@SharpAssKnittingNeedles]

The one with characteristic glow of uranium glass lit by uv radiation was my favorite 🥰

[@SEMIA123]

your grandfather invented the volume knob? Tesla bless your grandfather

[@Omnihil777]

Louder I CAN'T HEAR YOUUU ;)

[@kestasjk]

@juggliar That's like how Steve Jobs invented fonts.. if he hadn't someone would have 2 years later. The early form of a transistor sounds interesting though

[@FinnMcRiangabra]

@@kestasjk Did you just reply to a joke with a dig at the original video to the effect that J. Poliakoff's invention of some thing is no big deal because someone would have done it eventually? I hope not. That is the kind of thing an asshole would say. Did you invent that same thing first and have an axe to grind? It is easy to claim that a thing that a person has devised and put out into the world would have been devised. It is less easy to prove it or prove that the claim is interesting or important. It seems a bit like how you minimize Jobs's influence on font implementation on computers. No-one who knows anything about it would claim that Jobs invented typefaces. He did, however, push for the implementation of fonts that closely matched between computer and print.

[@kestasjk]

Mark M I understand a volume knob is just a variable resistor. if he invented the variable resistor okay thats impressive i guess, but otherwise hes just taking a variable resistor and finding another use for it, sorry I dont think thats a big deal. Based on your reply i thought maybe an analog volume knob was more than that, but no thats all a volume knob is

[@FinnMcRiangabra]

@@kestasjk I don't know the whole history of Mr. Poliakoff's claimed patent. However, the quote by you that I was replying to reads," That's like how Steve Jobs invented fonts.. if he hadn't someone would have 2 years later. The early form of a transistor sounds interesting though." Your claim basically devalues the entire point of the patent system. You claim that, yeah, that's interesting, but now that you mention it, it could work. But *You* never mentioned the original invention previously. It does not matter whether it is obvious after the fact. Did you patent the use of a variable resistor for volume control?? That is your claim? Where is your patent? People come up with great ideas every day. Sometimes they are "obvious". The way the system works is that the first person to claim the "obvious" is the inventor.

[@spinvalve]

I think gramps would be even more impressed that we viewers are sitting at every and all corners of the Earth. Shoutout from Singapore.

[@Livanskoy]

Russia here \o/

[@ionlymadethistoleavecoment1723]

Livanskoy cool photo

[@IndieMarkus]

and Austria!

[@langtonmwanza6689]

Zimbabwe here.....love this chanel

[@KabeerJay]

and India!

[@fevol_]

Your father invented the hearing loop? That's awesome! As a deaf person (Been deaf since my birth) with Cochlear Implants I'm very thankfull for all the aid, thanks to that, I can almost hear like a normal person. Loves from Belgium!

[@zecke58]

Felix Fevol *Grandfather.

[@BlackEpyon]

So you've been a cyborg since birth? Cool!

[@fevol_]

BlackEpyon Kind of! c:

[@AmusedToast]

I use hearing aids. Can I be a cyborg too?? 3:

[@derekirelandsirsmokepotalo1152]

@@fevol_ what do you mean like a normal person there is no such thing as normal we are all different that's what makes you... You. So happy you can hear big yourself up cause alot of people are trying to keep you down.

[@Yimbotron]

"Martyn's Historic Discharge" PHRASING.

[@quitteable]

Enter a name here in a box no less

[@JohnLeePettimoreIII]

Jonas Meyer A BIG box!

[@xxxmurray]

Yes, could have been phrased slightly differently. He admits he was a school boy

[@grendelum]

*_BEWM !!!_*

[@LaGuerre19]

"Don't touch"

[@Palifiox]

What a wonderful heritage. The tubes might contain uranium, used for a green or yellow colour since the late 19th century. Uranium glass is fluorescent under UV. The one on the far right at 1:50 looks a little like "Vaseline glass "which typically contains uranium and is slightly cloudy. Negligibly radioactive.

[@bkm83442]

+1 on the uranium glass.

[@darjiaethera]

I'm pretty sure you're right. It has the characteristic glow, especially in the one scene you mention.

[@caidurkan251]

Every time a video comes out on this channel I get very excited.

[@SyntheticFuture]

Your grandfather must have been an amazing man, and so are you. He could have never imagined you talking and showing this to so many people, and in fact talking about science to this many people. Take pride in what you do, it's well deserved!

[@adizmal]

This man is such a legend.

[@klimke22]

he reminds me of a british chemist genius version of Einstein

[@daedra40]

Thanks for another video. Very sentimental feeling all of a sudden when he mentioned the idea of years those glass tubes being 100 of years old but still able to live on in entertaining ideas. And then mentioning his grandfather was the icing on the sentimental cake. Prof Martyn : best entertainer/professor on the Interwebs.

[@Akula114]

Sir Martyn, thank you for sharing the story of someone who means so much to you, and indeed, to so many people around the world. Not only are his Geissler tubes fascinating, but just imagine if he could know how many lives have been touched by his genius. My utmost respect to you. In you, his genius and enthusiasm for the world about you are quite evident!

[@lxathu]

I feel honoured and also lucky to be given the chance to take part in this interesting remembrance.

[@Nets-nutsBr]

Dear Professor I really appreciate you sharing this about your grandfather. Please tell us more about him!

[@Tizocgringo]

Thank you, Sir Martyn, for sharing with us something from your family history that is special to you, your grandfather, and your family. I am very grateful to you for keeping these memories alive and also for your work in educating us about chemistry and other sciences.

[@Verynonspecificchannel]

show this to people who don't understand science. they're all like "YEAH, SCIENCE! what does it do??" you: "nothing.. it makes pretty colors"

[@Verynonspecificchannel]

yeah, your rgiht

[@1Howdy1]

What his grandfather used this for was experimenting with plasma to etch circuit traces into silicon. How do you create and hook up a few million transistors on an IC the size of a CPU? Plasma. Do a search for something called a "Plasma Etcher". I helped fix one of these in college back in the 90's that Intel had donated to the school. I've fixed everything from model T's to 28 GHz microwave systems - getting that machine to fire up and see electrical plasma flow like liquid was the most satisfying. To think his Grandfather was playing with this back in the 20's is just amazing.

[@Abdega]

1Howdy1 I helped build a plasma etcher for a lab I used to work in 😊

[@daveappleton2551]

Very non-specific channel anti vaxers are fact and science deniers

[@kaizah1997]

Finally my long search came to an end...this man is 66 years old!

[@tacmed1995]

I felt a sudden connection to you right now. I work at a healthcare center here in Norway, and one of the areas I am in duty of, is hearing aid. I requisitioned a hearing loop the other day. In norwegian it is called a "teleslynge". I love Periodic Videos, and the ones featuring you, are the best of them all. Thanks.

[@inhumanfilth681]

You are such an amazing person. If we all had teachers like you no one would ever drop out of school

[@guitarz667]

Look, here's the deal. It's absolutely magnificent that this man teaches so many people so many amazing things, but.... and here's the biggie... I absolutely love him so much because he makes me smile. It's cool when someone makes learning fun. Yes yes, is there a cooler Prof on the planet? I think not. I'm sure you've heard it a million times, but Martyn Poliakoff is the epitome and complete embodiment of the art of awesome teaching.

[@a.mathis9454]

Your grandfather would be proud that you have shown some of his equipment to over 300k people. Great videos! 👍

[@warmowed]

A very interesting piece of equipment! It was very generous of the professor to bring these out to demonstrate them, considering they are special to him and must be quite fragile.

[@screavics]

The videos you make will always be popular to most of us, the quality is perfect on every video from this channel.

[@Nellinator23]

Nice to get a bit of family history combined with such a neat little object. Lovely video.

[@DustinScottErickson]

Favorite video so far! Isn't it memorizing how far technology has brought us, and how quickly!

[@hwwwarrior90]

...a very poignant and heartwarming ending. Not only are the Geissler Tubes being shared with a larger audience than he could have ever imagined through means he would see as magic...they're serving as tinder for a knew generation of inventors and chemists

[@ArcAiN6]

i could listen to the prof all day. Very informative, and very entertaining.. Which is a very rare combination.

[@NicolasBana]

Isn't it uranium glass ? It looks greeninsh and it glows under UV light with this faint green

[@NicolasBana]

And it would be easy to test with a geiger counter

[@zaprodk]

Most certainly uranium glass. I agree!

[@lordsqueak]

Uranium glass would certainly fit with the time frame, and was the first thing I thought of when seeing it glow.

[@bgezal]

First rule of unboxing science equipment of the 19th century: bring your Geiger counter and never inhale.

[@myguiltybody]

I chuckled

[@pedromagalhaes9246]

Thanks to you Professor and all the team in Periodic Videos :-) Excerpt from NYRB: Tony Judt - Meritocrats "But I only ever became closely acquainted with one such person-my neighbor Martyn Poliakoff, great-grandnephew of the Poliakoff who built the Russian railways, a spiky-haired eccentric out of Westminster School who went on to secure a CBE, Fellowship of the Royal Society, and deserved renown as a popularizer of chemistry to young people. Hardly your typical toff."

[@Omnihil777]

I read about Josef Poliakoff, a grandfather you can be proud of! Awesome! Now I even like our Prof even more!

[@Muonium1]

A couple of the things the professor says in this video surprise me. For one, he seems to think the glass is doped with iron to make it yellow and fluorescent. It is almost certainly "vaseline glass" however, doped with uranium. A simple geiger counter test will affirm this quickly. Also, he is strangely under the impression that the determination of the gasses inside will be difficult and potentially destructive to the tube??? All the information to determine the gas or gasses inside is already there. You're looking at it. One can tell simply by observing the color alone that it must be either air, argon, helium, mercury vapor, or possibly but HIGHLY unlikely, krypton or xenon. The simplest spectral analysis even done with a handheld piece of cheap diffraction grating will immediately reveal which of these gasses it is. The lines of mercury are instantly recognizable, as are the quasi-continuous repeating bands of the many rovibrational transitions of nitrogen and oxygen molecules if it's air. All of this could be done in seconds with equipment that I'm sure his lab has around somewhere.

[@DrTeddyMMM]

Exactly!, when he said, "...the glass is lightly yellow..", my immediate thought was, "....that's uranium glass (vaseline glass)"....and as you pointed out, a simple spectral test would give the identities of which gasses were present in the tubes......something I did in early high school lab with a diffraction grating. Maybe some of the statements made were to spark comments?...only the Professor knows! :P

[@Swagodactyll]

A spectral test requires the knowledge of the pressure in the tube, which he doesn't have

[@Muonium1]

You do not need precise knowledge of the pressure to do a spectral analysis. You already know the pressure is substantially below that of an atmosphere because it is capable of being lit by a low power handheld tesla coil AND the discharge does not exhibit any filamentous self-pinched arcs as in a plasma globe toy. The pressure is FAR too low to exhibit any significant pressure broadening or doppler broadening effects and the tubes all appear to have both wide and narrow regions where diffuse and capillary discharges can both be observed separately. Spectral analysis would be so trivial here you really wouldn't even need a proper transmission diffraction grating and could probably just do it by eye looking at the reflection off a cd or dvd.

[@michaelcoulton883]

he said ion, it contains a uranium dioxide dissolved in glass

[@jaymiller3756]

Thanks so much for sharing this precious part of your family history with us, Sir P!

[@U014B]

7 people so far are leaking 100-year-old gas.

[@MegaTp4]

lol

[@pecfree]

Noel Goetowski 41 stickers by now

[@johnlbales2773]

Noel Goetowski What?

[@superchuck3259]

Very Very slowly!

[@sessionfiddler]

Wonderful legacy to have an audience for your work 100 years later.

[@JafarChou]

I love how he casually talks about his grandfather like "oh yeah, he invented volume control and the transistor". It just makes him more awesome.

[@electronicsNmore]

Excellent video!

[@wedmunds]

Professor Poliakoff whips out his 100-year-old discharge rod--and it still works like a charm.

[@todorkolev7565]

the ribs on these toys serve to enhance pleasure

[@Lolwutdesu9000]

Professor, your grandfather has so far entertained over a hundred thousand people. He can definitely rest in peace. This is more than he would have expected :)

[@bismuthboss3902]

Excellent video! You are the best Prof. I watch this channel mainly to hear you and your (awesome) stories!

[@billiondollardan]

Martyn Poliakoff is a treasure!

[@Mekratrig]

Always a treat to see Professor Poliakoff again. Surprized that the infamous and ominous Neil was kept off camera, somehow he seems very appropriate for Halloween season.

[@dayzimlich]

Hello, Professor! Thank you for sharing your grandfather's antiques with us. At 3:38 the glass glows a distinct greenish yellowish color. It looks very much like the pieces of uranium glass in my collection, which give the same color when activated by UV light.

[@ouTPhaze]

That was really cool, and it is kind of inspiring to think about how small the audience would have been back when your grandfather was still alive, compared to the audience it is receiving AS WE SPEAK!

[@SuperMattronic]

Wow, doing some background reading your whole family did amazing things. And i'm proud to say so are you Martyn. Keep it up!

[@pecfree]

over 232k people watched it. your grampa would be proud professor. bless

[@chromatogiraffery3104]

Some Geissler tubes are not purely decorative, they were used with 'Lecher lines' for measuring standing UHF radio waves, looking for the points where the glow died down as zero points or 'nodes'.

[@ElementalMaker]

Please check the yellow/green glass with a Geiger counter. It looks like it may be Vaseline glass, which fluoresces under UV, and looks quite identical to your samples.

[@pev_]

This is nostalgic to me because when I was young (nearing teens, almost 40 years ago) I went to the library often and was fascinated by books that taught science. There was one book that had various sort of DIY stuff about making high voltage experiments, including high voltage transformers and Tesla coils AND these tubes. It was fascinating but sadly my only attempt was not very successful. I attempted to make a high voltage high frequency transformer from a used car ignition transformer by stripping the cap from it so that I could access the magnetic core (laminated steel plates) to make a magnetic resonance switch to operate it in relatively high frequencies. I think I got close, but not enough, it never produced any satisfying sparks even :) And I don't think I would have had any clue as to where to get these wondrous glowing glass tubes either.

[@CasualSandre]

The true magnificence of these contraptions is that whenever these experiments are performed, they show how beautiful orbitals can be when excited :)

[@andregranum8115]

The greenish glass is "uranium glass", or vaseline glass (same thing). It's still used today in Geissler tubes, as it gives off a lovely glow when it's subjected to high tension electricity. The gas in the tubes is probably only residual air molecules, given the pink discharge in the bulbs. This is the most common thing for ordinary Geissler tubes, they are just evacuated to a fairly strong vacuum, and further colour is introduced to the discharge by adding vaseline glass and/or various liquids. The liquids are more difficult to identify right off the bat.

[@Vonargandur]

what an awesome heritage for an awesome man

[@ChrisDIYerOklahoma]

Yes Sir! There are 850,000+ subscribed to this Channel...def a big audience. I wonder if your grandfather knew Tesla (or Edison). It would be excellent to hear more about him in future videos. Thank you.

[@Renzsu]

These are quite magical, never heard of them! Can't imagine what it must've been like for those back in the day to see them.

[@joetylerdale]

It's an amazing feeling that he is there, right next to you, talking just to you.

[@cspann831]

I have been entertained as well as educated Thanks! Always enjoy these videos. I'm working my way slowly through all of them

[@Xaerorazor0]

From my work in spectra, I can almost assuredly say the inner tube is Quartz with a low pressure Mercury or Thorium Argon mixture, both used as standards in the astronomical spectrograph we have with somewhat similar coloring. The outer fluid and gases may have a copper or iron vapor but I can't be sure. I would actually use two types of spectral analysis Emission of a charged tube at a controlled voltage, and compare it to an absorption spectrum. Might be able to tease out the quartz and glass comp as well as the other elements in the tubes

[@jamdoodles]

This guy is absolutely delightful.

[@nikolas_schreck]

Thank you for sharing with us.

[@ralbiruni]

We are gratefull to your grandfather and you for this video!

[@brushhead]

Fascinating! I once had a book named the boy electrician and was fascinated by it. By today's standards almost all of the experiments described were truly lethal. It detailed how to make a spark coil which provide arcs of over three inches. This would be about 30kV. It also described experiments with X-Rays. It also mentioned Giessler Tubes so was quite interested to see one. From memory argon was blue, helium was yellow...can't remember any more.

[@AJsWargaming]

Thank you for sharing this wonderful family heirloom. I was certainly fully entertained.

[@DeoMachina]

How nice of the Professor to dig these out for us all :D

[@24framedavinci39]

That's so cool. Thanks for showing us that. Wish you guys made videos more often though.

[@kurtstory9466]

The bright green glow seen in glass at 3:00 and 3:39 could be due to some UV light striking uranium-doped glass, creating green fluorescence. Uranium-doped glass was often used in lighting because it has a lower coefficient of expansion when heated.

[@Liamv4696]

Amused by the thousands of people watching this video. Pretty sure he'd be more amused by the moving speaking picture device :D

[@bgezal]

Reverse engineering the apparatus might prove as many questions and answers as the Faraday candle lecture. I'd love to hear Sir Martyn do an episode on just this. BTW I'm sure his late grandfather is as excited about the youtube audience as he was for his grandson's CBE and other titles.

[@TheRealL4dsharks1]

Thank's for sharing this with us professor!

[@dionpierre5847]

I love how enthusiastic he is about chemistry

[@themegaspud]

The reason they work with only one electrode 'connected' is that the tubes have a capacitance. As the supply is AC current flows in and out of the tubes and therefore they are supplied with energy which they convert into light.

[@NukeET2]

Thank you again, Sir Martyn.

[@Gohka]

The fact those things are upwards of 100 years old and still working is astounding. Considering a barely used light bulb in my house might last a year and that serves a functional purpose, not just pretty for the sake of pretty.

[@mattlogue1300]

My grandfather invented too, more of improved upon the CRT tube to make it much slimmer and operate at lower voltage. He also helped a guy known as Oppenheimer on something.

[@joshuarosen6242]

It definitely entertained me. Thank you.

[@vkoskiv]

I find it quite amazing how Sir Martyn here is showing this stuff to us on KZbin, and he knew and is related to a person born 140 years ago :D

[@squidcaps4308]

Ah, that Poliakoff. Wow, i'm sound engineer and have installed hearing aid induction loops and of course; volume control is #1 tool so just.. wow... Absolutely wonderful, i feel so warm now, almost charged..

[@buddha4242]

these tubes have extremely high scientific value! precisely because of the questions they provoke. phenomenon, questioning, and discussion based reasoning with models is the future of science education! you just need to make sure you don't spoil all the questioning fun for the students (less explanation). thanks for the cool videos!

[@LuigiRosa]

Professor, thank you for sharing your grandfather items.

[@guitarz667]

Absolutely phenomenal.

[@IDoNothingImportant]

Science is the best thing ever and this channel makes me happy

[@TGC40401]

If you can tell what gases are present on a planet in another galaxy, you can tell what gas is in those tubes.

[@lawrencedoliveiro9104]

Which planets do we know of in another galaxy??

[@LividImp]

As I was watching this, an alarm on my phone went off. I set it yesterday to play X's "Blue Spark". Life's freaky coincidences.

[@WereWade]

Thank you for the presentation! It is an honor to hear your insights into the scientific world.

[@spaceghostcoasttocoast9343]

wooo! I missed your vids guy! Good to see you back. :)

[@periodicvideos]

we have some crackers coming in the next month or three!

[@spaceghostcoasttocoast9343]

Periodic Videos can't wait. I love your videos, they are so interesting.

[@Guitarm4n99]

Great! Please have more really new and interesting things like this that aren't found in other corners of KZbin. Things like the elephant toothpaste videos were kind of nice, but I'd like to see Periodic Videos keep setting itself apart from all other chemistry like it always did. Thanks for your time!

[@gavincurtis]

Love these videos. Just relaxing for some reason listening to him explain things.

[@TheCyberd1]

Let me first state I am not a chemist so I may be way out of line with these suggestions. Couldn't you use a spectrometer to narrow down what the gas may be? Also, is it possible to regulate the power output to see how much power it takes to start fluorescing which may give another clue? You can use an Ultrasonic Thickness Gauge to check the thickness of the glass. All of these tests are nondestructive, then all you need is to solve for what the pressure might be. Well, I hope this helps, always love your content. Thank you for posting it.

[@flaplaya]

So cool to see in many peoples eyes such nerdy things. I wouldn't mind seeing the Professors vacuum tube collection either. Maybe?? It would be a winner.. This man grew up around the time Bell labs invented the transistor.. The "glory days" as we are being dumbed down today it seems.. Great video of 160 year old technology which is still amazing.

[@flaplaya]

I stand corrected. Joseph Poliakoff invented the transistor in the 1920's I am shocked at how amazing this bloodline is. I am shocked.. True genius.. Yellow glass is Uranium doped almost always back then hence the fluorescence.. Over and out, amazing video Professor Sir Martyn Poliakoff.

[@JonasClark]

Geissler tubes are generally made of plain glass (the clear), I've not heard of any in quartz. The yellowish glass is indeed uranium-oxide glass; Corning termed it "canary yellow" and, filled with argon + mercury, neon sign makers got an electric yellow-green. The gas inside is almost certainly air at low pressure. These are probably circa just before or after 1900. The tubes mounted on a glass pedestal or foot seem to be especially rare; more common for upright tubes was ending with a thin stem, which was inserted into a wooden pedestal, and many of the decorative fluorescence-effect Crookes tubes (containing a painted metal beetle, butterfly, flowers, etc. or maybe a fluorescent seashell or some minerals in glass claws) were so mounted. There were several fluorescent liquids used, giving everything from yellow, orange and red to green, blue and purple. The yellow-orange in the liquid-filled tube is probably fluorescein, and the clear which glows blue is sulphate of quinine. The tube with the glass vase is a "Gassiot's Cascade," wherein the discharge is forced down into a vessel with the lower end sealed, and must then 'climb' out over the rim. This was exploited in other tubes so that a watering can might shower light, a fountain would appear to spray, or a pitcher would pour a stream. These three are exceptionally beautiful, and have survived in great shape. The electrode caps that are missing is very common. Be careful with the spark coil, as those sparks can puncture glass around electrode wires. I'd love to locate one of the glass pedestal type someday. Oh, and Professor, you've got approaching 300,000 views by now. You and your grandfather, and his wonderful and rare Geissler tubes, are entertaining a whole lot of people, many of whom have probably never even heard of these, and some of whom may have seen only the simple ones used in modern school classes.

[@Ryvucz]

Interesting stuff, thanks for sharing.

[@periodicvideos]

thank you for watching!

[@RanchOwnzU]

nice comment, nice response very civil, very yummy. cooked to perfection

[@kinglambent]

Greetings fellow warrior with the strength of the Falcons claw.

[@greground7494]

Respect to Sir Martyn Poliakoff.a true inspiration.

[@r1w3d]

this is very entertaining. thanks for the three of you who did this video👍

[@rodrigocastaneda84]

Thank you so much Professor! I love your videos and anecdotes!

[@dercebe]

Just my two cents: The green glass is almost certainly uranium glass, which is a weak aplha source, but was used for its nice flourescence when exposed to UV light which amlost always is prodiced in gass discharges. ( look at 7:03 ) Many ot these tubes were simply filled with air at reduced pressure . Mercury is not completely unlikely, but not really needed.

[@damonkernbach6676]

Did anyone else notice that the box he took those out of were labeled "Martin's historic discharge"? Best part of the whole video.

[@hobbified]

They're lovely, and the fact that they still hold vacuum after all this time says a bit about the workmanship as well.

[@mrpiexpat1239]

so happy to get this notification!

[@serioushex3893]

those look so cool! i love the colors they make!

[@BertNielson]

Thank you for this! Simply delightful and very entertaining.

[@isettech]

Time to view the spectrum of; 1 the non fluorescent portion to identify the gas by the spectral lines, and 2 the fluorescent glass to view it's emission lines. It would be very interesting to identfy the gasses. Due to the very strong emission lines of In low-pressure mercury-vapor lamps at 184 nm and 253 nm, they would be preferred for fluorescent displays. Normal window glass would block the UVC and quartz would pass the short wave UV.

[@QqJcrsStbt]

The vote seems to be for uranium glass. Could be thorium glass (high refractive index) goes yellow with age. Uranium glasses are often a bright green. A gamma spectrometer could answer that one (NaI crystal plus scintillometer or solid state semiconductor detector). Not sure that a GM tube and counter would discriminate.

[@detritus10001]

AWESOME! I've been dying for a new episode!