He chants and gestures. The water cools down and turns bright pink. (This is a cantrip, so it's good for little tests.)

Sara blinks down at it, "Huh. That's what it was supposed to do?" She glances up to confirm, "It's a little colder, along with the pink." 

"Yes. Spell called prestidigitation. It has minor magical effects, on up to a cubic foot of material."

"Huh. I'd classify that as an illusion spell, if it was our magic. I can tell it wasn't, though - I'm still connected to this, I would've noticed anyone else's mana. That's low tier, I'm guessing? I guess it doesn't explode on contact then." She unpicks the water ball, the liquid pooling pinkly in her palm and dripping onto the floor, where it sinks into the stone to the water veins below. She eyes it for a moment, then looks back up at him, "Another?" she asks, already drawing another thread up, "I can put it somewhere other than my hand, if you want to try something that might hurt me if I'm touching it."

"It's transmutation, not illusion, though it'll revert after an hour. That was the lowest tier. Higher level things might do damage to you, and the highest level I can cast would be hard to restrict just to that. But I have a spell that could turn it to acid prepared; anything else would require waiting until tomorrow."

"And that will be a transmutation too?" She guesses, "Alright." She reaches out and casts another sphere into the air about ten feet away from them, "Whenever you're ready."

And he turns it to acid.

Now she's holding a ball of acid in her magical grip. She doesn't know what this tells him, but it reminds her that the water ball spell can hold most liquids, though usually the farther you get from pure water the larger the thread it takes. She glances over at him, "What does this tell you?" She asks, "It tells me that I can cheat at controlling acid if you cast that spell on water I'm already controlling," she adds, "Which could be useful in a fight." 

She reaches out with another thread, hooking into the ongoing spell, and spreads the sphere out into a disc; this is technically free-casting, but she's good at minor water manipulation. Usually that would take more mana as well, but the costs are the same as if she were working with pure water. Interesting. 

"The water doesn't meaningfully count as something you're affecting. Can you try hovering a solid object somewhere, while I try to use a telekinesis spell on it? Lower-level telekinesis spells only work on unattended objects. It's unclear currently if your magic counts as 'attending' to an object."

"Hm," she says, "Alright." 

She leaves the acid hovering; better not drop it in here, she can take it outside and drop it one of the training fields later. 

Just about everyone has a pool of Space-tinted magic, just from everyday summoning and levitating. She draws a thread up and pulls a coin out of her coinpurse with it, lifting it to just above head height between the two of them, "This works?" She asks. 

He tries to push it around with mage hand; it doesn't go.

"The telekinesis didn't work."

"Alright, so if I'm still connected to the thread my spell is using, you can't affect it?" She pauses to wrap the thread around the coin, letting go of it with a quick, "Float." 

"Try now?" She suggests.

That works! He scooches it.

She grins, "There we go!" 

"I bet you can affect permanent effects, too. Is there anything you could do with our lamps? They're Illusion-Fire enchantments," she adds, "So people can see without catching their books on fire." There's the ones on the wall, or there's the ones in the library. The ones on the walls are fed by the city and might count as being controlled by the Healer, but the ones in the library, and the ones people carry around for personal use, are unattached but rechargeable. 

"Maybe. Is there one I can experiment on?"

"I can myself make permanent, heatless lights that are attached to specific objects. They consume some resources - specifically rubies, to channel the arcane energies - to make them safely, but I'm an experienced enough mage I can skip that somewhat. The permanency spell for other effects is a lot costlier. I haven't tried enchanting an already magical object before - it's usually difficult to impossible within our own magic system."

"But the different systems might mean your magic doesn't consider objects enchanted with our magic to be magical objects. Enchanting objects with our system involves carving them, so you can only do as much to an object as you can fit the runes for onto it. If we could double enchantments using the two different systems... Well, I don't know what we could make off hand, but it would certainly be something interesting!" 

She pulls out her own lamp and trots over to the lamps on the wall, touching them together to charge her lamp from the city's veins, "You can use this one," she tells him. It's shaped like cube with an empty sphere in the middle of it, leaving the center of each face open, a long handle extending from the top. Each face is covered with runes. After a few moments it lights up, the center glowing a soothing pale blue, and she sets it down on the counter under the wall lamp and steps back, "Here." 

He'll try to make it glow yellow, first.

It glows yellow! 

After a moment of this, it goes out. 

"I was using it all last night," she says, "It's out of mana. If you have the materials you need you could try enchanting it, though?" 

He shakes his head. "Even the most basic of enchantments takes eight hours of work, and a lot of material."

She nods, "Okay. Um. Do you want to try the wall lamp? To see if an Artefact being in control of it stops you from affecting it?" 

"Sure."

He'll try changing that one's color, too.

No go. 

"Guess that counts," she says. She looks around, fishing for other ideas, then shrugs, "Can you think of anything else to test?" 

"Do you have any enchanted objects that aren't glowing already? I have a short-term light spell."

She goes through her pouches briefly, before lighting up when she touches the bag with the tiles in it, "Oh, I have my stylus with me," she remembers, pulling out the tool she was using earlier to etch runes. She sets it on the counter, "Will this work?" She asks. 

"Just fine."

And he casts a light cantrip on it. It should start glowing like a torch.