"No!"

"Gases under pressure are strong stuff. Heat up water into steam and it'll push out of a kettle with a nice whistle. Attach some mechanism to a boiler that's making steam - I can sketch it later, how I think it's supposed to work - and it will create motive force. A lot stronger than a mule or whatever, with an 'engine' that is big enough and efficient enough. The newest ships have steamer paddles to go up rivers or pass through windless harbors faster. I know very little about how it actually works, the gears and such, though."

"You getting this, Vasil?"

"This unit is recording this conversation."

She slows down to focus enough to sketch a diagram in the air... "So you let steam in here, and it pushes this bit which pushes on the wheel, and then the wheel is heavy enough to keep turning until it goes here where the steam in the cylinder gets let out, and then it starts again... This is, like, a painfully simple one and really inefficient I think though."

"But once we get the concept down and popular I bet people will improve on it very fast."

"Probably... And I think I just remembered the first big improvement they made... Let it let in steam at both ends of the motion and exhaust in the middle. Engines are good for milling without rivers, or big pumps to move water around, or for ships and trains."

"Converting energy seems like it might be useful in general, and we might get good things out of combining magic with that."

"I'm no engineer, but I could've been if I didn't get magic. You mean, magical heat? That would be much cleaner than coal."

"Yeah, make a spell to heat water up, use that rather than burning anything, might be more efficient. Would need some maths to figure it out, but yeah."

"It'd swing back and forth depending on if magic or coal is more scarce. Want to do the Witch-youngness-efficiency-math now?"

"Magic is probably more scarce, and yeah!"

"We already have units for magic, though they're a bit fuzzy for different-efficiency reasons..."

She puts one-tenth of an Erg into her amulet and passes it backwards. Enough to fly at this speed for about half an hour. "One tenth of an Erg. I produce about four Ergs per day now, and average prime-age production is six to eight. How much can you do with this much?"

They discuss some magical mathematics and eventually reach the conclusion that a young Witch is enough of a mana fountain to match twenty mages. Kaede whistles, impressed, when they reach this conclusion.

But then a thirty-five year old Witch would only match ten, and a fifty year old five, and an eighty year old one. And they're less efficient for many things.

Interesting.

"But that's definitely enough that we could keep you young forever and have a lot of mana leftover."

"Too bad Witches are only about one in a thousand, back home. Not enough for everyone."

"And mages are about one in two hundred, here, but metamancers a lot less than that, probably. And... I wonder if a metamancer could make someone a Witch."

"How would you even try that? ...And you'd need a volunteer."

"Would that be hard to find? And I don't know how to try but I would."

"Volunteers would not be hard to find at all on my world. Probably harder here."

"Oh yeah here they'd be nigh impossible to find, but I'm relying on a way back to your world being doable."

"Yeah, lots of the grand plans we're making seem to be relying on that."

"Not necessarily, they can still work here they'll just take longer."

"Can you be distracting - I just..." She looks like she's going to be sick or is trying not to cry or something, hunched over.