Let's Measure Magic Power!

The results of the functional testing for the seven wind-instrument ritual magic implements at Magic University were fairly decent.

Although it was possible to activate magic containing one unchantable sound—the Night Witch's magic—the implement apparently developed cracks after just one use. It might have one or two uses left.

Moreover, the Gremlin in the seven wind-instrument ritual magic implements was neither spherical nor geometric in shape, so the magic-power amplification multiplier ended up at 0.8×.

Even after accounting for the twenty-percent reduction in power, the fact that humanity had overcome one of the unchantable sounds was enormously significant. It was far better than self-destructing in a single blast from abnormal vibrations, too.

They are currently carefully analyzing the precious data obtained from the initial experiment in hopes of further development and stabilization.

Going forward, they reportedly plan to start over with the painstaking task of recruiting experts knowledgeable in spatial geometry and acoustic physics, then investigating the relationship between shape and effect in greater detail.

Advancing the research looks like it will take quite a while. Well, that's how these things go. Everything does. I hope the university professors and students will do their best.

Just send me the research results in writing. I'll be waiting.

Meanwhile, I was pondering the mystery of the black Gremlin in my own way.

After getting cozy under the charcoal kotatsu, drinking homemade doburoku and snacking on river-fish-skin crackers (hooray for the liquor tax law disappearing on its own!), I came up with the hypothesis that it had been structural color.

If the black coloration of the black Gremlin had been structural color, I still wouldn't know why it had turned to dust, but I could explain the reason for its unusual coloration.

Structural color is, as the name suggests, color created by structure. Color can be produced not only by chemical pigments, but by physical structures as well.

For example, when you turn over a compact disc (CD), it appears rainbow-colored depending on the angle you view it from. That's structural color. The tiny ridges and grooves carved into a CD to record data refract light, making it look rainbow-colored without any rainbow dye.

Structural color also exists in nature. The vivid colors of peacocks and hummingbirds are produced by light refracting through physical structures rather than by pigments. The blue of blueberries and morpho butterflies is the same. In fact, 99.9 percent of the blue found in living things in nature is structural color. That's why concepts like the bluebird of happiness and the miraculous blue rose exist.

Structural color, which seems like a marvel of physics, is actually a fairly common feature for living things.

Which means...

The black Gremlin of Daidarabocchi might have been structural color as well.

Daidarabocchi must have been an animal before mutating into a monster. It wouldn't be strange if it had possessed some form of structural color, and that color had manifested in its Gremlins.

In other words, all of Daidarabocchi's Gremlins were copper-red. One of them—the smallest—had fine grooves in its physical structure, and simply looked black because of the way it refracted and absorbed light.

That's my hypothesis.

I can't explain the transformation into dust, but the color makes perfect sense.

To test my hypothesis, I decided to carve structural color into a Gremlin.

Since black is a color that reflects no light at all, I started by carving a physical structure that absorbed light into the surface of a random Gremlin. At perfectly regular intervals of 500 nanometers.

The Steel Sheep work gloves were comfortable to use and didn't interfere with my fingers even during such delicate carving. I couldn't exactly do it effortlessly, but after a full day's work, I had carved a one-centimeter-long groove that produced black structural color in the Gremlin.

Rubbing my bleary eyes, I took another look at the structural-color Gremlin.

Hmm, it had certainly turned black. Even though I hadn't used any black paint at all. This was structural color. It was strange, even though I understood the theory behind it.

I took off my work glove and poked the structural color to check whether it would turn to dust, and that's when something strange happened.

The instant I poked the black structural color with my fingertip, the black turned white for just a moment. It wasn't an illusion. I definitely saw it.

This time, I didn't just poke it. I pressed my finger flat against it. The black structural color promptly turned white.

Then, when I pulled my finger away, it promptly turned black again.

Oh?

What a fascinating phenomenon.

Hmm. Is this reacting to human contact...?

No, that's not it. Temperature? Magic power?

I tried touching it with a finger cooled by ice, and with a finger warmed by a hot-water bottle, but apparently temperature had nothing to do with it.

It also didn't work through gloves. It had to be bare skin—or rather, direct contact with a body. Whether I used my elbow, cheek, or tongue, it reacted by changing from black to white.

It seems to be reacting to magic power, doesn't it?

It might be reacting to vitality or lifespan, too, but all the various effects produced through Gremlin processing so far have involved magic power or magic. It was safe to assume this was related to magic power and magic as well.

Even when I pressed the structural-color Gremlin against the three fire lizards dozing in the morning haze at the reverberatory furnace, it changed from black to white only while I was pressing it against them. There didn't seem to be any individual—or rather, species—differences in the color-change reaction.

That was as far as I could go with tests I could perform alone, so I summoned a specialist in magic power.

Naturally, it was Hiyori.

Hiyori was roused from sleep early in the morning and came through the disorienting fog looking rather displeased, but she cooperated with my investigation of the structural-color Gremlin while grumbling under her breath.

"Hmm. It certainly changes color."

Hiyori placed a finger on the structural-color Gremlin and nodded as she spoke. I eagerly asked her a question.

"Hey, is this color change related to magic power? It doesn't seem to have anything to do with an intrinsic color."

"Wait. I'll look into it."

Hiyori said it briefly, then became completely still. I couldn't tell what she was doing, but she was probably using magic-power control somehow.

Hiyori, who will grant a request even when I drag her out of bed first thing in the morning, really is my best friend!

But I also get dragged into midnight consultations when she suddenly says, "I want you to listen to me," and makes me advise her on whether she should accept a part-time lecturer position at Magic University. So we're even. Let's just say we're two peas in a pod.

Hiyori remained motionless like a statue for a while, her finger still touching the structural-color Gremlin. Then, without warning, she removed her mask, brought her face close enough for the tip of her nose to nearly touch the Gremlin, and stared intently at it.

After remaining that way for a little while, the structural-color Gremlin began switching between white and black at incredible speed.

Something's happening! I have no idea what she's doing!

But I am a legendary wandmaker capable of waiting when told to, so I swallowed all my questions and quietly waited until Hiyori finished her investigation.

Another ten minutes or so passed before Hiyori pulled her face away from the structural-color Gremlin and put her mask back on.

"I've mostly figured it out. This Gremlin reacts to how much magic power a person has."

"Oh? Tell me more."

I knew it was something related to magic power.

But the amount of magic power a person possessed?

So it's a magic-power measuring device?

"This shows the amount of magic power I currently have left. Watch... There. When I throttled back my magic power and lowered the pressure—in other words, pretended to be out of magic power—the gauge dropped, didn't it?"

"Ooh!"

I had no idea what sort of magic-power control Hiyori had used, but I could see the result of it with my own eyes.

Hiyori had a finger pressed against the edge of the structural-color Gremlin. Like a volume gauge being turned up, the black Gremlin turned white from the point of contact outward, then turned black again.

I could clearly see that the horizontal lines spaced 500 nanometers apart, which I had carved to produce the structural color, were functioning like the marks on a gauge.

When Hiyori said, "Increase the magic power," the markings on the black structural color turned white, and when she said, "Decrease the magic power," the white markings turned black again.

Both the principle and the appearance were easy to understand.

The set of 500-nanometer structural-color lines carved into the Gremlin had become a magic-power gauge!

"The amount of magic power remaining and the markings are directly proportional. Look—when I doubled the amount of magic power I was applying to it, the width of the color change doubled as well."

"So it's correct to understand that this structural-color Gremlin has become a magic-power gauge?"

"That's right. A witch or wizard can change the markings as much as they like this way, but there's no doubt it can be used to accurately check the magic power remaining in people who can't control their own magic power."

"Seriously? I've been waiting forever for this feature...!"

I could practically see an insanely hype, big-win victory animation playing out in my head.

I trembled with emotion.

Until now, I had never been able to quantitatively measure magic power.

We had no choice but to measure it using standards like a witch's subjective judgment—"You have a lot of magic power"—or, "You only have enough magic power to cast the core spell of shooting magic, \"Shoot,\" once, so you don't have much."

However.

This structural-color Gremlin allowed us to see the amount of magic power a person possessed, as well as their remaining magic power, by reading the markings.

We had acquired a ruler for measuring magic power.

In other words, until now humanity had been researching magic while relying on vague, fuzzy expressions like "a length about as wide as your thumb and forefinger spread apart."

But if we used a structural-color Gremlin as a ruler, we could conduct research using concrete values like "188.2 millimeters long."

Both the precision and scope of our research would increase by leaps and bounds.

A revolution. This was a revolution!

Good grief. I had set out to solve the mystery of Daidarabocchi's black Gremlin, and accidentally created something outrageous.

"Dai, celebrating is fine, but this Gremlin can't measure all of my magic power. It goes past the scale. Actually, even your magic power would overflow the scale, wouldn't it?"

"Leave it to me, leave it to me. Once I understand the function and the theory, it's as good as done. I'll improve it in no time, so wait!"

The inspiration circuits in my brain were already blazing.

I threw myself into making a structural-color Gremlin capable of measuring Hiyori's enormous reserves of magic power.

First, I started with a simple proof-of-concept experiment.

The Gremlin I had given black structural color using 500-nanometer-wide horizontal lines was so sensitive in displaying detected magic power that even my own magic power caused it to overflow.

So I tried making structural color with horizontal lines 700, 600, 400, 300, and 200 nanometers wide.

I found that the narrower the horizontal lines, the less sensitive the magic-power display became.

In other words, a Gremlin carved with 200-nanometer-wide structural-color lines could precisely measure even a witch's absurdly vast reserves of magic power.

I confirmed that a melt-and-resolidified Gremlin displayed the amount of magic power it possessed in the same way as a natural Gremlin. Around the time I was conducting this experiment, Hiyori got bored and went home. I then cast four twenty-centimeter-long Gremlin rods.

Then I carved structural-color lines 500, 400, 300, and 200 nanometers wide into the respective rods.

Even I struggled with processing on the nanometer scale. Although I worked ten hours every day, it took fifty days to finish applying all four types of structural color to all four rods. And I had gotten used to the process and sped up along the way. This ended up being the most labor-intensive job I had ever undertaken.

But thanks to that, I could now precisely measure the magic power of every person, witch, wizard, and monster.

I could measure my own magic power, the fire lizards' magic power, and even the ridiculously huge magic power of that Blue Witch.

I sent the four great structural-color Gremlin rods to Tokyo Magic University as the reference standards for a new system of units that would open up a new world.

Gahaha! Tremble in fear and collapse!

Without a doubt, this is super-advanced technology that no one but me could ever create.

You can designate it a national treasure, too!