Vulc nods. "I have enough Terram on me to cast it once," he says. "I can lend it to you, just write something down saying something to the effect."
He casts the ritual (36 + 4=40, within 10 of the spell level but he is down two long-term fatigue levels.
Since it's unlimited uses and the item maintains concentration, the trigger is just "whenever it touches an object." No additional levels required for that trigger.
"The spell lasts but a moment and then dissipates." Six seconds is much longer than "but a moment." To me that means, long enough that something happened, but without ANY perpetuation-- Conc/Diameter is the minimum spell duration for any kind of perpetuity.
If that's the case then there's no point in being Range:Touch. If you're enchanting the Room and the Target gives you everything inside that room, then make the Range personal (affecting the Room itself without need of affecting everything the Room touches).
No. Each time the effect enacts, it affects one target, using one charge. Yes, it maintains concentration on multiple effects simultaneously. I stole that idea from you, using Arachne's talisman to maintain concentration on multiple individual spells simultaneously.
Really? I'm sitting next to a pretty small bookshelf, and it has 74 TPBs/HCs on it. A large bookcase would hold a lot more.
We probably can't get all the lab texts onto one bookshelf, but lab texts are cheap, and one large bookcase will definitely hold all our summas and tractati.
Any more, I picture books in Ars Magica looking like The Lineages and Histories of the Great Houses of the Seven Kingdoms from the series.
Yeah, that's true. Well, we could certainly prioritize the protection of our main summas and tractatus over all the commentaries.
I can't tell if you're right or wrong on this.
Anyway, it’s better to err on the side of caution, so let's go with diameter and a linked trigger.
By RAW, if range is Personnal, the target can never be larger than individual (... In the corebook: Hermetic Projects has a R: Personnal, T: Structure enchantment*).
I tend to think this was done with magi in mind and not magical items, so I would allow if for a room or structure.
Yet, this would mean you must have your laboratory outside of it, which may be difficult, or even impossible if it is one room in a building.
Yet, you keep having troubles with ranges and targets:
Ars Magica p111: “The range of a spell is the distance to the nearest part of the target of the spell. Thus, is the caster is touching the external wall of a room, he can cast a Target: Room Corpus spell on the people within at touch range, even though he is not touching any of those people and indeed cannot see them.”
Ars Magica p113: “Room: the spell affects everything within a chamber.”
Range: touch is needed if you enchant an item that'll cast the spell on the room, which is what I wanted to to. Building a laboratory outside the library seems a daunting task to me. An item can be stolen, but also means that, if the library is destroyed, the enchantment isn't lost and can be used with the new library.
Ah, ok.
It would work, sure, but here’s the catch: Without someone or something to direct it, it begs the question of “how will it cast the effect on the right book, and not on the same again and again?”. We need either a quite intricate trigger, or a linked InVi effect, which would defeat our purpose :-/
Good one. This is, mostly, a YMMV question.
To me, a summa isn’t necessarily a single book: A poor summa (low Quality + Level), sure, but good ones may be spread over several volumes, just like the Lord of the Rings is spread over 3 books.
Likewise for size. Some medieval books were quite tiny. I prefer our mighty tomes of magic to be arm-sized, big, and dusty.
So in short, the question is: Do you want andorra’s library to be massive, sporting hundreds of massive books which, in game terms, translate to dozens of summae, or do you want it to be about a hundred small books?
I saw it as the former, which is why, in my calculations, I always included a Size + 1 modifier: To me, the library is very, very big and chockfull of dusty tomes. Yet one could see it as the later, and have a library that’s just a normal-sized room with a few bookcases, thus sparing the extra magnitude 
EDIT: Had forgotten my notes about the exception to R: Personnal in HP.
I think that there has got to be a simpler and more abstract way to go about it.
How about a magic shelf (or whatever). It is enchanted to cast whatever effect on each individual book/volume of a book, Concentration/Item Maintains/Unlimited Use. No trigger, putting the book on the shelf is the item activation procedure Maybe you got to shout a magic word at the same time (and again at Sunrise/Sunset), I dunno, but not complex enough to need a trigger).
Yes, this is Ryu's idea.
You need a trigger, in this case, putting a book in it. This works finely. A +3 trigger for automatic activation at sunrise/sunset would be nice, yeah, or else it won't work on books in place.
Now, to work in the first place, it would mean that, for our library, we chose the "few books of small size" option rather than the "many books of huge size" one. This is a possibility, it's just un-mythic in my opinion.
The trigger would work for putting the books in, unless somehow people put more than one book per round.
Books in place... Less so :-/ We run into the "one target each round" problem: There's no way to have it discriminate per se on which book to cast the spell 
It would probably work randomly, so in time (say, after one hour), all books would be covered, but this is quite imperfect
Now, note:
Concentration + Maintain = Sun Duration
Unlimited = Room target.
So, anyway, even if possible, this changes nothing:
MuAn(Te) 05 + 1 Touch, + 1 Conc = 15, +5 item maintain concentration, +10 unlimited uses, +3 activates at sunrise/sunset = lvl 33
vs
MuAn(Te) 05 +1 touch, +2 room (assuming our library is a simple room, then, and not a massive chamber), +2 sun = lvl 30, + 4 constant = 34.
So, IMO, either we drop the idea, we hire a contractant, or we do it as a greater item
Vulc favors the Greater Item.
I agree. Slotting centuries of Hermetic knowledge on a single bookshelf just seems...wrong.
I'm coming around to doing it as an invested item, provided we can afford the vis. I'd prefer the Room effect, or better yet, a comparable Structure effect.
Strike me for an idiot.
That's a great idea!!! That way, we could make every animal-related product in the covenant building uninflammable! Of course, we'd need to have food cooked outside, but still, this is awesome!
Now, we just need to figure out who has the best total, and whose help he needs Arachné is willing to.
Vulc can open the building (he can handle 36 pawns in a single season) but that doesn't solve the problem of "having a lab big enough to fit around the building." I don't see that rule specified anywhere, though, and I think having a lab inside the building should be sufficient for enchanting the building. (Also, if there was a Room/Structure enchantment on it already, what happened to the gigantic outside/around-the-tower lab afterwards?)
The Mystery of Hermetic Architecture was used for the original enchantment. That is pretty much the only way to enchant a building or other structure that does not fit inside the Lab. The whole scaffolding thing and building a cheap & disposable lab around the building, that was JL's idea and not anything I would have thought of.
If you could enchant a structure by building a lab in it, there would be no need for Hermetic Architecture. The best you can do is enchant the room that the lab is in. Even that is a bit wonky, but is something I would let fly.
The Valdarian lineage, having been cut off from most of the Verditius Mysteries (those outside what their line has preserved), has a tendency to dabble in other mysteries. An example would be the spirit magic of Dimir Taar. Another example would be Daern filius Valdarius, who was a member of the Piliar of Hiram.
Thanks! 
I still think I'm missing something. Making every animal product in the library nonflammable may have some side effect we're not seeing yet. This also assumes we're accepting the Warping effects as the price of doing business, but I think we were doing that anyway.
Probably Vulcanus. Most of us have similar levels of Mu and An.
I'm not talking about enchanting the building - I'm talking about enchanting an item with a Structure/Touch constant effect and mounting it somewhere in the library tower. It would (probably) take less vis, avoids the problem of building a lab around the library, and gives us the freedom to select any advantageous shape(s) and material(s) we like.
Not necessarily. Just because something is an Animal effect doesn't mean that it has to effect every animal product equally. That's why we have Spell Designs and not just the 50 TeFo combinations 
. If you design a spell so that "All books within the Structure have a +50 Soak vs. fire or Ignem effects for the duration of the spell" or whatever, then you can still have a hearth, a stove, an oven, tallow candles, and so on.
I agree with Peregrine's perspective.
(say that 3 times fast!)
lightbulb OH! Yeah, okay!
Yes, most of the times, enchanting an item is better, the only drawback being that it can be stolen more easily.
Facepalm
Oh, yes, of course we can limit spells... I even wrote something like this in a warping thread... Thanks, PB
BTW, sometime after the Dragon discussion, Arachné will fight her reluctance and try once again to approach Vulcanus, hoping that their convergence on this point will help.
I'm quite worried about this situation. Hopefully, things will go well, but if they don't, we need something to fight back.
Now, maybe the enchanted balistaes carmen and I are building will do the trick, but I wouldn't count on it. His scales are probably way too thick, they would only scratch him. Likewise, I don't think I can craft a potent enough might stripper to affect him, despite it seeming the best option we got. What about you? Is there something you can do should we face him?
...I don't know how I never saw this post.
"With a little experimentation, I could craft a low level Might stripper with seven points of penetration in one season... which is probably insufficient," Vulcanus says. "Now, I could probably get better results putting it into a sword, at Touch range... which we could probably get eight magnitudes of penetration out of. But if we're going to make an item for the job, I'd want to be sure we get what we need. I'd say we should aim for ten magnitudes of penetration, minimum. I could probably do that in a single season with some assistance."
Arachné nods
I agree. I believe he's proved powerful enough to pass through the covenant's aegis once, so 8 magnitudes won't be enough.
She pauses, clearly thinking
What bother me is that, anyone wielding such a sword would be the prime target of the Dragon's wrath. I know you don't fear death, and trust in your courage, but I don't think anyone going toe-to-toe with a dragon would survive long enough to seriously wound him :-/
Now, we have little other choice. Being able to hurt him, even a little, is better than being defenseless.
Hum... Maybe... I'm currently working on a series of rings that'll allow us to have an enchanted ballista at our command. Now, I don't think it'll be able to hurt him. But hopefully, I'll be able to craft a few enchanted bolts that might be able to achieve the same effect as your sword. Not a lot, sadly, but hopefully, working together, we might be able to strip him of two to four magnitudes of might before he skewers us.
Carmen was initially poised to help me for two seasons, but I had mangled my astrological calculations, and her help won't change anything for me. We should talk to her, and see if she'd help you instead.
I wonder, this sword of yours, is it a lesser item? If yes, it might be worthwhile to enchant a greater one. Should carmen agree to help you instead of me, you would be able, for the same magnitude of penetration, to achieve a much greater effect than anything my bolts could do.
Explanations:
We dumbly forgot that lesser items couldn't be done over 2 seasons, so I had to work over 3 on my own. Carmen is thus free in the last season of 1231 and first of 1232.
As an aside, she can craft charged Might Stripper bolts, although achieving such penetration taxes her abilities, she can't do much of them, unless the wastes a season on this, which she's unwilling to do. And she must do it in a single pass, so, for that penetration, might 05 is the best she can do.
Now, if vulc, with some help, can do a might 05/pen 50 sword might stripper in one season (lab total around what? 70? 
), he can probably do a might 15/pen 50 in 2 seasons, which would be much more efficient.
"I have donated into the covenant armory an invested sword with plenty of room for further enchantments," Vulc replies. "In full armor, I am difficult to harm physically. Fire or acid may be more of a problem for me, though. But I am willing to wield the blade against him, if necessary."