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[JWFokker]

I noticed that pitchblende is included in the list of upcoming minerals and there's a note regarding it's use for making yellow glass. To me this seems to be something of an anachronism, as uranium oxide wasn't used for this purpose until the early 1800's. Previously it was only used as a pigment for ceramic glazes.

[Gaulgath]

Yes, but 18th century Earth didn't have dwarves.

[Toady One]

Wikipedia has a source claiming the year 79 as the earliest confirmed date, and another for the late middle ages, which is what I was going by, although it says its use was popularized later on.

wikipedia on uranium glass

[JWFokker]

quote:Originally posted by Gaulgath:
<STRONG>Yes, but 18th century Earth didn't have dwarves.</STRONG>

Thanks for that witty and predictable response.

quote:Originally posted by Toady One:
<STRONG>Wikipedia has a source claiming the year 79 as the earliest confirmed date, and another for the late middle ages, which is what I was going by, although it says its use was popularized later on.

wikipedia on uranium glass</STRONG>

The problem with Wikipedia's entry is that they don't include the criticisms that have been leveled at that information and the questions that it creates. First, the Roman glass that was discovered in 1912 is the only sample ever found containing uranium from that time period. There haven't been any more samples like it discovered since. And that raises the issue of why it went unused for nearly two millenia. Silver was the predominant ingredient used to create yellow glass until the 12th century when glassmakers began to use lead-tin oxide, (which later fell from favor around 1750).

[Veroule]

It is largely a question of availablity of the mineral.  Different minerals will be used depending on which was discovered to work by whatever group of humans are bring the trade into the area.  Then if they can't get supplies of that mineral anymore they start trying others and ultimately find another that works.  So a small supply of pitchblend was available in some areas near Rome.  As its ran out various wars and things destroyed the knowledge of using it and other materials were found elsewhere.

It is rather like early electricity.  I believe it was something like 1000BC that some basic voltaic cells were dated to.  However there seemed to be nothing they were used for, and of course electricity was a basically forgotten for a long time.

[Toady One]

As far as the anachronism goes, since I don't know anything about glassmaking or the development of glassmaking, is the problem based more on the availability of uranium oxide and that it might not be immediately obvious to use it for this purpose, or is there some intermediate chemistry that has to be done that really is out of the realm of possibility without substantial supporting technologies?  As far as what goes into the game text files (when I actual get around to coloring glass in a less simplistic way than I'm doing it now), it will probably depend on which kind of anachronism it is.  The real-world timeline isn't so important to me in this case as what would be feasible.  On the other hand, certain things like firearms which wouldn't be so anachronistic against the real-world timeline are less likely to be put in on different grounds.  Regardless of the decision, the raws will be moddable, but I would like to know more about the feasibility of the uranium glass coloration using early methods.

[JWFokker]

It is possible to make yellow glass from pitchblende if the composition is almost exclusively uranium oxide, but this doesn't often occur naturally due to radioactive decay, which results in enough thorium and lead impurities that if raw pitchblende were used for glass coloration it would produce a brownish orage glass and not yellow. It wasn't until Thomas Cock managed to isolate uranium oxide by extracting it from pitchblende during the first few years of the 19th century, that glassmakers would have been able to achieve a consistent yellow coloration using uranium oxide. As I mentioned previously, silver was the first element used to create yellow glass, followed by lead-tin and lead-antimony.

[ June 04, 2007: Message edited by: JWFokker ]

[Toady One]

Okay, I've poked around a bit more and found a Glass Association article about this (here) that corroborates your information.  I'm not sure at this point exactly what Thomas Cock did, but in any case, I'll leave the glass coloration out and leave the pitchblende in for ceramics (although I was unable to find a reference for that that didn't use pure uranium oxide with a quick googling).

[Tamren]

Why take it out? Sounds like a job for the alchemist.

[Veroule]

Alchemy needs something.  Making soap for dwarves that never have a Bathe job is just silly.  A history of chemistry shows that much of the early research in that area came from Alchemy.  The word alchemy has just been bastardized through connotation over the years.

[Toady One]

Unless I learned more about exactly what the guy did, the year does make it iffy.  People had begun to understand quite a bit batteries and electricity around that time, so it's possible the purification process for uranium oxide is really more advanced than I want to get into.  For the stock universe at first, I just wanted to stick with things that were plausible as much as possible, since this works as a guide for how the raw tags can develop in a sensible and coherent fashion.  People can mod in whatever they want.  The stock alchemist or whatever workshops the alchemist splits into will have more than enough work without worrying about a nebulous uranium oxide reaction.

[irmo]

quote:Originally posted by Toady One:
<STRONG>Unless I learned more about exactly what the guy did, the year does make it iffy.  People had begun to understand quite a bit batteries and electricity around that time, so it's possible the purification process for uranium oxide is really more advanced than I want to get into.</STRONG>

I guess that means no aluminum.  Drat.

Extracting uranium oxide from ore is fairly low-tech.  One procedure involves dissolving it in nitric acid, then precipitating with lye.  This gives fairly pure sodium diuranate, which can go directly into the glass.  That's well within the reach of medieval alchemy, though you might not want to do it in a cave.

(Actually extracting the uranium, for Armok-knows-what reason, does require electrochemistry.  It also involves a huge amount of hydrofluoric acid, which is unbelievably nasty to handle.  Before you consider building a nuclear weapon to use against the elephants, please consider how this will look: This is a finely engraved image of a dwarf.  The dwarf's face is melting.)

[Keilden]

Melt Faces FTW

[JT]

Christ, that's scary as all hell.  We were using dilute HF in my shop class in Grade 9 in high school.  I was a bit behind on my project (making a metal door-knocker) while the other students had moved on to the glass etching.  Many of the students would etch their glass, go to the sink where I was busy polishing the faceplate in a sinkful of water, and wash off the acid into the sink.

I didn't think anything of it at the time, and didn't feel anything when they washed off their projects, but about two hours later my hands were stinging.

If that had been concentrated HF, I could've been in serious medical straits. =P

[edit](Actually, now I'm starting to wonder if that's why I had juvenile arthritis in my ankles in the later grades in high school.)[/edit]

[ June 05, 2007: Message edited by: JT ]

[Toady One]

In home room, there was an announcement on the PA from a science teacher, along the lines of "I've just spilled some butyric acid in one of the lab rooms, so the whole school may smell like vomit for part of the day."  It did.

Actually, irmo, I was curious about aluminum.  I know getting it out of bauxite is a pain, but there was a cryptic wikipedia sentence:  "it is very rare in its free form, occurring in oxygen-deficient environments such as volcanic mud".  When they say "very rare" do they mean microscopic, or do they mean enough you could make something fun out of?

He he he, there are a lot of things we are currently doing that you might not want to do in a cave, so I can't let that stop me.  In any case, according to wikipedia, it seems a lot of the standard acids were discovered around 800 AD by the same guy, so that seems to be fair game.  It'll be interesting to see where the lines should be drawn.  There's also the matter of separating out discoveries which were relatively simple but 'late' and discoveries which really required lots of building blocks.  If I allowed all of those simple discoveries, I wonder if the resulting universe would look too alien.

[ June 05, 2007: Message edited by: Toady One ]