"Well then, let's explore a few ideas," Jin said.
"It'd be good to have a few proven results to show if we want to launch the Three-Dimensional Magic Circle Research Society, after all."
If Jin simply asked, approval would easily be granted with a single word from on high, but that wasn't what he wanted.
"How about we try making something simple, something practical, and something with broad applications?"
"That sounds like a great idea," Kachea agreed.
They needed something for general use, and something to demonstrate that this was worth researching with an eye toward the future.
"For something simple, maybe magical lighting?" Eira chimed in, pondering what they should do.
"Yeah. That would be simple, at the very least, and practical too." Jin agreed with the idea of making a magical light.
"The core concept would be gathering free ether from the surrounding space, converting it into mana, and activating the Light spell. That should be it."
All they had to do was make it switchable, Jin explained, outlining the magi-sequence.
"Yeah, that'll work....Come on, Jin, don't steal my thunder. I wanted to say that," Eira complained with a wry smile.
"My bad, my bad....So, for the design, maybe something you could place on a bedside table or a desk to illuminate your hands?"
"Yeah, something like what Jin described sounds good."
"Alright. I'll make the stand itself, so Eira, Kachea, you two work on the magic circles," Jin said, dividing up the tasks.
"Reiko, lend me a hand."
"Yes, Father!"
Reiko brimmed with enthusiasm now that her turn had finally come.
(Secretly procure a small amount of high-grade wood from Laojun....Just enough to build a stand will do.)
(Understood.)
Jin whispered his instructions to Reiko so Eira and Kachea wouldn't overhear, raising a sound-insulation barrier as an extra precaution.
A mere twenty seconds later, the teak wood was delivered.
"Oh, teak, huh?"
In the modern world, teak was celebrated as one of the world's three great precious woods, alongside mahogany and walnut.
Hard and durable, it resisted rot even in seawater, giving it a wide range of uses, such as ship decks, doors, furniture, and bridges.
When polished, it took on a unique luster.
One interesting quirk was that silica (silicon dioxide) sometimes precipitated inside its vessels—the conduits that transported moisture—which could dull the cutting edge of blades.
Using that teak, Jin set about crafting a magical desk lamp rather than an electric one.
"Finished."
The design incorporated a bit of Japanese-style flair, giving it the appearance of an andon lantern.
The base was a square measuring twenty centimeters on each side and five centimeters thick. From there, two posts extended upward, supporting a cylindrical, paper-covered lamp chamber.
The Light spell would activate inside this chamber.
Since it generated no heat, there was no risk of fire.
"We're done over here, too."
They had inscribed a three-layered magic circle onto a relatively inexpensive magi-circuit plate.
The first layer gathered free ether, the second layer converted it into mana, and the third layer cast the Light spell.
A switch was attached to allow the first layer's magic circle to be activated or stopped.
It was a straightforward mechanism—in essence, it toggled the device on and off by disconnecting or linking a segment of the magic circle.
Fitting the three-dimensional magic circle made by Eira and Kachea into the housing Jin had built took barely a minute.
They immediately tested it.
"Switch on."
When Jin flipped the switch, the light came on after a delay of about one second.
This lag was a drawback of the magic circle system, but for a lighting fixture, the three of them deemed it perfectly acceptable.
"It's plenty bright!"
"Yeah, this is definitely practical. If we inscribed it onto a slightly larger plate, or used two layers just for the circle that gathers free ether, we could probably make it even brighter."
Eira pointed out the insights she had gained from actually putting it together.
"We can leave that as a task for down the road."
"True. For now, that takes care of the lighting fixture."
"What should we do for the one with future potential?"
It was still only 3:30 in the afternoon, leaving plenty of time to make something else.
"Hmm, personally, I'd like to try making a mana power source."
Generally speaking, that meant a combination of an ether converter and a mana driver.
"The output for that fluctuates wildly, right? Wouldn't that be tricky with a magic circle system?" Eira countered.
"Well, yes, but finding a way to make it work is what contributing to technology is all about, isn't it?" Jin countered in return.
"Fair point, but do you have a plan?"
"I do."
"Oh? Let's hear it, then."
"Of course."
Jin began to lay out his idea.
"What we're about to make probably won't be the finished version. Think of it as a prototype," he prefaced.
"First off, the reason the magic circle system isn't suited for applications with fluctuating output is because its response time is sluggish."
"Right."
To put it in simple terms, the mana had to circulate through the magic circle repeatedly to be amplified.
While not entirely accurate, it was similar to accelerating charged particles in a cyclotron. The more cycles it completed, the more it accelerated.
Therefore, the time spent circulating resulted in a delay.
That duration was roughly 0.4 to 3 seconds.
Compared to current golems, which had an average response time of 0.1 seconds—and 0.04 seconds for high-performance models—this was far too slow.
"That's why we add a capacitor."
"A capacitor?"
It was a term primarily used in electrical circuits, referring to a device that temporarily stored an electrical charge.
Using a water stream as an analogy: one function of the magic circle served as the water source, while the capacitor was a small tank. A faucet was attached to it, supplying power to things like a Golem Engine.
When the water source didn't have a high flow rate, storing water in the tank beforehand ensured a steady supply without issue, even if the faucet was frequently opened and closed to vary the volume drawn.
"Aha, I see."
"So that's your idea. As expected of you, Jin-san."
Hearing Jin's analogy, both Eira and Kachea grasped what he intended to do.
"The equivalent of the tank is, literally, a mana tank. A small one should do the trick."
"That makes sense. In other words, by steadily trickling power into the mana tank during normal operation, it can handle sudden spikes in demand, right?"
"Pretty much."
"It's a great idea. In that case, the most expensive magi-device would be the mana tank."
And mana tanks could be manufactured relatively cheaply.
"Hmm, in that case, it's definitely worth researching at Go-lab, too!"
"Right? Plus, since it has general-purpose applications, I think other research labs could make good use of it as well."
"It really is worth researching!"
And so, Eira, Jin, and Kachea set to work on prototyping their new magi-device.