Lyra, Bon Bon, and the crusaders were all sent home long before the sun set, with Starlight escorting them for protection. The remaining hours between the crusaders wonderful discovery and their departure had been spent compiling all I knew about the magical circles.
It wasn't very much. Even after they left I sat looking over about two dozen pages of notes that summarized what I knew about spell forms. There was three or four times as many papers stacked to the side that could be generously called theories. Truth was, they were mostly just guessing.
Did you really have to use Machina for everything? Unless she comes back, the most powerful circle you have can barely heat soup.
"You're one to talk. You can rearrange the stars to escape your lunar prison, but you can't provide a simple spell for cutting wood?"
I can provide a spell that can slice through nearly anything, but most of what I know or Princess Luna used was destructive or restrictive. You want constructive magic. Besides, you were supposed to e the great dimension jumper, able to decipher new languages, conquer kingdoms, leap tall buildings.
"All with the aid of my companions. This was so much easier when I had Machina to memorize everything and project what I needed to draw."
It may not be a total loss then.
I leaped back from the table as an arcane circle of dark blue fire burst into existence.
"Put it out! PUT IT OUT!" I hissed, beating at the ethereal flames with my jacket. Nightmare sighed and the circle vanished.
I was only trying to help. There was a pouty tone to her voice.
"Well do that when we are certain Lance isn't going to come bursting in here. He's already wearing tin foil under his helm AND he won't take those cold iron boots off. Next thing I know he'll be looking for garlic."
"Why would I need garlic?"
I spun round to find Lance standing apprehensively in the doorway.
"Are you talking to yourself again Sarah?"
"No, I'm talking to Nightmare. She's telling me that her bond is manifesting as some 'blessing of the moon' and I'll need to avoid garlic." I grinned at him. "The good news is I'm getting a lot stronger. Now if you could just give me a pint or two of your blood-"
Lance disappeared so fast it would have made Rainbow Dash jealous.
When are you going to learn that sarcasm is worthless against him.
"He's always good for a laugh."
"Sarah," Lance called, "your visitors are back!"
I looked up from where I was scrubbing the massive magic circle off the tile in the Day Court with a bit of worry. "The crusaders or the other two?" I reached for my practice sword, trying to remember the defensive training Steel had pounded into me in the two days since their first visit. I didn't want to hurt them, but I had no intention of getting caught off guard again.
Bon Bon poked her head around. "Good afternoon Sarah."
I had to smile, and moved my hand away from the sword. "Hello Bon Bon. Did you and Lyra come back to discuss humans again?"
"Lyra did, but I've got something a little different for you." The mare walked in and sat down, pulling books out of her saddlebags. I walked over and picked up the first one.
"'Thaumaturgic Theories in Ley Lines and Nexus Construction'?" I looked down to see the rest of the books had a similar theme.
"I spoke to the local librarian and she suggested these books to aid you in your construction based circles. She's even willing to lend them to you-"
"Wait! The local librarian is Twilight Sparkle!" I dropped the book on the pile and backed up a few steps. "No, nuh uh, no way. The last time I legally, reasonably borrowed books from her she hunted me down with a determination bordering on psychopathic. You can take those back right bucking now!"
Bon Bon was stunned by my outburst and waved a hoof to calm me down. "No, listen. I told her about you and the castle and she is willing to let you borrow these books long term in exchange for copies of the books in your library."
"Sure," I said, waving at Lyra as she staggered in, her saddlebags overstuffed. "I'll just add 'copy all of the books accurately with my off hand' to my to do list. I can schedule it along with carry bricks, research magic, research humans in Equestria, aid crusaders, rebuild castle and find way home."
"It won't be that hard." Lyra said, "Twilight gave Bon Bon some copy books."
Bon Bon lifted a thick leather book with a brilliant diamond in it's center. "You place a book on top of it and it makes a copy."
"How much of Lyra's power are you going to need for that? I was hoping to experiment with the magic circles today."
"None, that's what the gem is for."
"Really? Show me."
"Hang on a second." Lyra said, dumping out one of the overstuffed saddlebags. "We have RESEARCH to do first!"
"OK, I'm looking at this, but I'm still not sure what I'm seeing." I said, looking at a large map. Several large arrows were drawn on it, flowing from from small regions and branching out. At each branch were small drawings or taped on pictures of tools, door knobs, or other odds and ends.
"It's a trade map, showing the spread of doorknobs, shovels, and a few other things." Lyra said, "Twilight helped me put it together."
"So this is where these items are coming from?" I asked. "But what is with the splits?"
"That's where variations are made, usually using the original item as materials." Lyra explained.
"So you think the lands these items originated in are where humans used to live?"
"That's the idea." Lyra said, grinning.
I looked over the map, following the arrows and reading some of the country names. All the paths passed into or through Equestria, but none originated in it. I traced one of the arrows back to an imposing range of mountains. "What land is this?"
"Those are the gryphon lands." Lyra said, "I bet they found the ancient artifacts from humans!"
"I'm not sure they needed ancient designs to come up with a pickaxe." I said. "If the gryphons mine the mountains at all, that tool would be a pretty basic item." I looked over my notes. "Don't gryphons have claws that are kind of like hands?"
"Um, kind of." Lyra said, unconvinced. "There was an obnoxious one in town a couple of years ago, but I never got a good look at it."
"Bon Bon, can you hand me that book of foreign creatures?" I asked, pointing at a textbook on Xeneology. I flipped through it, looking at the lands and kingdoms each creature called home. "Look at this Lyra, every item comes from someplace with creatures with either claws or hands. Dragons, Gryphons, Minotaurs, each item originates somewhere like this." I stared at an odd creature in the book. "What are Canids?"
"Oh, I know those." Bon Bon said. "We have a pack living near Ponyville called Diamond Dogs. They can dig really fast and prize gems over everything else. They used to kidnap ponies as slaves."
"So all my research was for nothing?" Lyra asked, looking tearfully at the map.
"Not necessarily." I told her, "You know that some of the items were created by creatures with claws and hands. Just remove those items and anything left might still have human influence."
The chance that anything was made by humans is slim to none. I've been around for centuries and never encountered anything like a human before you.
Lyra picked up a book of xenology and began reading through the entries, looking for creatures with claws and folding the corners down. I turned to Bon Bon.
"So, you were going to show me the gem powered copy book?"
She looked up from where she was sitting and grinned. "Sure, check this out!" She picked up a tome from the library shelf and put it on the stone table. Next she laid the copy book on top and tapped on the gem. There was a soft glow from the gem, and as the glow faded, the pages of the copy book seemed to glow. It lasted a few minutes before the glow of both page and gem faded out.
Bon Bon, with a flourish, opened the copy book to show me the first page of the original tome, copied perfectly.
"That is amazing!" I said, pulling the books over and flipping through them for comparison. "Any limitations?"
"Oh tons," Bon Bon said. "It can't copy books with magical seals and circles because of interference, it can't copy a book bigger than the copy book itself, and they are expensive to make."
I flipped the book over, seeing that the gem inset could be removed with a bit of work. "How much charge does a gem have? How much can it hold? How do you charge them? Is charge dependent upon size, type, clarity, cut-"
"Whoa whoa whoa!" Bon Bon waved her hooves in the air trying to stop the barrage of questions. "Geeze you sound like Twilight. I don't know the answer to most of that, other than most gems just kind of absorb ambient magic. That's why there are things like rock farms."
"You....are going to have to explain that one."
"OK, so there is power, magical power, all around us." Bon Bon said. "And anypony, or creature I think, can use it. Most of it manifests as just little things. Earth ponies can grow food faster and better than it might naturally grow, and pegasi can fly and walk on clouds. Gems sort of collect that power so it can be used."
"So in rock farms earth ponies move rocks that have the seeds of gems, like little shards, around so they can absorb the magic in the area. It's a slow process, and there are few who are good at it."
"Can't you just get a unicorn to charge a gem for you?"
Lyra looked up from her notes. "I've tried it before, and it's really tough. If you use too much power, or go too fast, then the gem just goes flying or can explode. I even heard of one pony who tried to recharge her gems, and ended up melting them."
I didn't even want to know how they did that. Still, if there was a way to use gems in my circles, then it would cut down on needing Lance to power everything I did.
And if a unicorn could charge a gem, there was a slim chance Nightmare and I could work out a circle to do the same.
"OK, enough human talk for a bit, it's time to make some circles. Now," I propped open one of the books and picked up a piece of paper and a pen. "How do I drive a nail?"
Two hours later and I was pulling nails out of wooden blocks, stone benches and brick walls.
"Well," Bon Bon said from where she was crouching under a distant table. "I'd say that last one was a big success."
"Look, with every new circle we learn something." I said. "The first one showed us which direction was which."
Lyra stared up at the ceiling, her horn glowing and her tongue stuck out of the corner of her mouth in concentration. "I'm not sure I can get this one out of the rafters."
"The second circle showed us that we needed to dial back the power. The third showed that we needed some sort of 'stop' trigger."
"Well, at the rate you're learning, we will all be pincushions by the time you're ready to do anything. What marvelous lesson did you learn from this particular disaster?"
"My circles are very power hungry. Also, don't leave drawings of circles and loose nails near gems. I think I owe you one of those copy books."
"Aww." Bon Bon said, "Those are expensive."
"But this is great!" Lyra said, bouncing up and down. "You've basically mastered nails in the first day. We should try learning how to spin things so you can make screws next, or maybe even how to cut stuff!"
The library door banged shut.
"..... Bon Bon?"