Telesphoros

Makes sense. I'm not sure it'll work, Kelsier might try to replicate the experiment anyways, but it makes sense as a motive for Harmony.

You're right, and I just realized why I think the Set created atium - it's because of what Harmony says to Kelsier What Harmony says here suggests that every time you do the harmonium/trellium reaction that atium and lerasium are created, and the lerasium subsequently destroyed. At least one part of it is obviously a lie - We know that Lerasium was not destroyed. But...the section about testing also contradicts what Harmony says earlier. If Harmony doesn't know how Wax's experiment was different, how did he test it again? It suggests, at least to me, that either Harmony was lying about not knowing to Wayne (which I agree, he has no reason to do) or he was lying about having replicated the results (which I'm also not sure why he would do). It's possible that everything he said to Kelsier was a lie, but then why tell him about the reaction at all? If the atium isn't created every time the reaction occurs, then if/when Kelsier tests it, he will discover the lie. If it is, then he should discover lerasium as well.

Marsh is explicitly looking for Atium. As far as Harmony's talk with Wayne, he's specifically referring to Lerasium. Atium doesn't even come up in that chapter. I think there are basically two possibilities A: Harmony's information was bad - the Set did create both lerasium and atium, but didn't realize they had done so. Given that Harmony spends most of the book completely unaware of what the Set is doing beyond generalities, this doesn't seem unreasonable to me. Even VenDell is shocked by the results of Wax's experiment, suggesting either Harmony didn't tell him similar experiments had already been conducted, or Harmony didn't know. B: Harmony is correct and Wax did something different. We have no way of knowing what, because we don't know what experiments the Set conducted.

Definitely a strong possibility. I do think it's possible that the Set created lerasium without realizing it though - we know for certain that the Set must have created atium, both because Marsh is on that trail and because we see it created during Wax's experiment. Despite that, no one in the Set uses atium - even assuming they didn't have any staff on hand who were atium mistings, I would assume that they'd launch a search for someone who was. Even one atium misting could have the ability hemalurgically removed and given to one of their operatives and they'd been experimenting with harmonium for years. It would give them an enormous, possibly unbeatable advantage. Both lerasium and atium were emitted from Wax's experiment as particles - the atium was only found later, as dust on the floor. Entirely possible that the Set just thought they had a new explosive and didn't bother to test the debris. Another alternative, in line with Karger's hypothesis about Intent, is that the Set was intending to create a weapon and so they did. Wax was intending to create Lerasium and Atium, and so he did.

Some notes on reviewing the chapter - we don't have any of the details on how the Set conducted their experiments, we just know that they did. The reaction that Wax did was not complete - the bulk of what they found after the explosion was Harmonium, with only residual atium and lerasium, so most of the Harmonium must not have reacted. “Harmonium,” he said as Steris dug out an extra vial of oil for him to put it into. “Plastered across the back of the box. I … think the experiment failed. It didn’t divide.” Additionally, the only reason we have to believe that the Set experiments didn't create Lerasium is because Harmony told Wayne that but A: Harmony had admitted that his sight was extremely limited and B: Harmony outright lied to Kelsier about the creation of Lerasium during Wax's experiment. So I find that conclusion a little bit suspect.

Huh. I thought it was kind of obvious why Bavadinium acts like that, though I fully admit I could be wrong on this. Bavadinium is created by Autonomy, structured by the Intent and purpose of the Shard. Going back to a WoB "Autonomy wants to remain Autonomy. Autonomy does not want to be corrupted by anything else." https://wob.coppermind.net/events/332-jordancon-2018/#e9608 The reason why it acts like that has nothing (IMO) to do with Autonomy being opposite and everything to do with it wanting to avoid being corrupted/interfered with by any other Shard's investiture. It repels investiture of other Shards in order to remain Autonomous from them. I agree that Ettmetal is unstable as a reflection of Harmony's instability. Edit: Harmony outright says "Autonomy is driven to divide off from the rest of us, to go her own way".

There's another possibility as well - that two Shards is not balanced but it may be possible to combine more than that. It depends a lot on the nature of Adonalsium and how it was split, which we know pretty much nothing about right now, but it might be that while two Shards cannot be combined as it would not be a stable configuration the full sixteen might be, with different aspects of each Shard playing off one another without actually cancelling each other out.

This might be me being too much of an amateur physicist - but I think it literally is a nuclear explosion, amplified by the power in investiture. 1: Harmonium acts like a heavy, possibly transuranic, element. Allik warns Wax not to store too much of it in one place, otherwise "odd things might happen". We know that the Axi of harmonium is likely composed of Lerasium and Atium, given that the reaction produced both. It seems likely to me that harmonium is literally a combination of those two elements, with the Intent+Investiture of Harmony providing the binding force sufficient to overcome their natural repulsion (both of Intent and electromagnetic). 2: We know that Bavadinium strongly repels Harmonium "more like it had the same charge". 3: We know that passing an electric current through Harmonium comes close to, but is not sufficient to separate Harmonium into Lerasium and Atium. So I think what happens is when the current is passed through Harmonium and Bavadinium is brought close, that is sufficient to overcome the binding force of Harmonium - Lerasium and Atium subsequently separate and release energy, just like in nuclear fission. The atoms of Lerasium and Atium which split subsequently collide with other Harmonium atoms with enough energy to split them as well, in the classic chain reaction. It's a very odd combination of physics and magic, and I'm sure the mathematics on it would be incredibly fuzzy, but it matches the description of Wax's experiment. With a more powerful current or something like modern compression implosions they should be able to fission Harmonium even without Bavadinium.