i am looking for comments on this enchanted bookcase.
The device needs to be opened with 5 pawns of vis. Empty Shelves will require 2 paws, and 3 pawns are needed for Library Porter. Library Porter is based on A Simple Charm for the Recovery of Misfiled Books out of Covenants. I am not sure if Empty Shelves needs a +1 for complexity.
This bookcase, made of beech wood, hides books contained on its shelves. A person can walk up to the bookcase, request a book contained therein, and it will be transported to the person's hand.
This enchantment makes invisible the contents of a bookcase's shelves; to all who look at it, it appears empty. The bookcase itself is visible.
(Base 4, +2 Sun, +1 Part, +1 level for 2x per day, +3 levels for environmental trigger)
ReAn (He) 20
Pen +0, unlimited use
This enchantment will transport a book contained on the bookcase's shelves to the hand of the caster. An arcane connection is required for the book, which is usually the library's catalog.
(Base 1, +4 Arcane Connection, +1 Herbam, +10 levels for unlimited)
You don't open an item for enchantment based on the powers you want to invest in it. You need to pay the full cost based on its Material and Size as per ArM5 p.97 -- in this case a wooden item (2) of either Large (x4) or Huge (x5) size. So opening the bookcase for enchantment would cost 8 or 10 pawns of Vim vis, regardless of the effects which are invested into it during the following seasons. The number of pawns serve as a limit on the effects that can be invested afterward, but it needs to be paid in full right from the start.
How is making the content of the shelves invisible a Rego Terram effect? It seems more in the province of Perdo Imaginem to me. --> already corrected, I see.
Using R:Per and T:Part to affect the content of the bookcase is debatable. The books exist independently from the bookcase; I probably wouldn't consider them to be Part of the bookcase. As a result, I think that the power should be R:Touch and T:Group. Perhaps I would be more amenable to the idea if this was a Muto Imaginem effect to make the bookcase appear empty, rather than a Perdo Imaginem saying that it makes the content invisible.
How can you activate the power if you are not in contact with (or at least quite close to) the bookcase? If you are close enough to activate it with a command word, than it seems fairly useless to invest an effect that does what you can do with your hand (though you might have to pull a number of books until you locate the one you are looking for). Unless the bookcase is large enough to hold hundreds of books.
Overall, the device seems pretty much pointless to me. There are better ways to hide the books, IMHO
Thanks for the pointer on cost of investing an item.
If I was to use Muto Imaginem, then I would need to penetrate magic resistance. But if I change to Group/Touch with Perdo, then I don't need to penetrate. Correct?
I like the idea of not having to rummage around for the book I want, hence the second effect. And, I am not trying to optimize for the best way to hide book(s). I just had an idea about a bookcase like this and wanted to figure out how it would work. This is my first crack at an invested device.
Indeed, by using MuIm the effect would probably need to penetrate, as it is the iconic species that are changed. Otherwise, a viewer with magic resistance would not be able to see the bookcase at all -- but that may not be a bad thing if the goal is to hide the books.
PeIm would not need to penetrate, since it is destroying the iconic species. But although the content of the bookcase would become invisible, it would still cast a shadow. Thus any source of light would reveal where the books are. To avoid that, you would need either Cr and Ig, or Re and Ig, requisites.
If I were to design the device, I might be tempted to try a different tack. Craft a bookcase with a false bottom and a second set of shelves hidden behind it. Fill the front of bookcase with mundane books. Enchant an effect similar to Library Porter to teleport a book to the hidden shelves. Enchant a seperate device to retrieve a book using an arcane connection (the catalog). Voilà! The bookcase can now be enchanted as a lesser item, saving you all that Vim vis. And the retrieval item can be used from anywhere.
Just to illustrate that in Ars Magica there's always three ways to do anything...
You might consider a ReMe effect similar to The Shrouded Glen; anyone in the room looking for a book in the bookcase never finds one worth taking. Base 3, +1 Touch, +3 Room, +2 Sun, +1 level for 2 charges, final level 26 + any Penetration you add on. This is a constant effect. There would be an Ease Factor to see through the effect, 12 or higher, and once you do see through it (as the magi within the covenant would, once the caster shows it to them), they don't have to roll anymore.
Yes, such an effect has to penetrate.
Often, the choice of enchantment effects comes down to which magus has time to make it, and what Arts he or she favors. But a library case like this makes a good item for sale at various Hermetic Fairs, probably with just one enchantment on it so it can be a Lesser Item. Only a Verditius carpenter would spend the time to craft library shelves like this with the intent to sell them to other covenants, and he could load them up with additional enchantments to, for example, ward the books against fire, vermin, and water damage.
Following illusion rules described in Calebaïs book, when you create illusions you lure all five senses. A PeIm on the books of a storage would destroy all species (without Finess).
So the books become invisible, cannot be taken nor eaten (sorry little worms), and cannot be smelled. Book usually don't speak so the sound effect is useless (if you have magic books which are able to talk, they will mute).