Echo 4

I really want to carefully observe the process of activated gemstone micro-particles in the bloodstream emerging onto the skin's surface.

This is the echoscopy device for that purpose.

We already know gemstones are present in the blood, but we can't possibly examine each blood vessel individually. Collecting all the blood in the body isn't practical either. So this device allows us to observe the inside of the body easily and without causing any injury.

That's the voice-altering crystal. I don't fully understand how it works, but when activated, the crystal changes the voice of the person using it—somewhat like a piezoelectric element.

Sound is the noise people produce.

Sound is vibration in air or objects. In other words, anything that vibrates can transmit these vibrations. The crystal must be controlling these vibrations.

Then, couldn't we generate ultrasonic waves? Ultrasound machines use ultrasonic waves.

Moreover, there was another point—William helped me with practicing the use of magic. The difference between using magic stones and using magic itself—where exactly does it lie? After repeatedly practicing, urging William to form a clear mental image, the accuracy of his magic improved.

What matters most in using magic is having a clear mental image of the physical phenomenon you wish to cause. Furthermore, having a scientific understanding of natural phenomena increases the success rate of magic.

Therefore, if I focus on a strong, precise mental image that includes an accurate understanding of the physical phenomenon, couldn't I use magic even with the voice-altering gemstone to generate ultrasonic waves?

I must accomplish a great deal in a short amount of time, or I won't be able to help anyone.

First, I need to test whether I can use magic with the voice-changing gemstone to achieve ultrasound imaging. Once I can harness magic at that level, I should be able to apply it to manipulate physical phenomena—understanding the reflected sound waves should then be within reach.

I recall the physics of sound I studied in high school and university.

I try to infuse the magic stone with every formula and characteristic I can think of, but it doesn't become a spell—only its function as a magic stone activates.

If the hypothesis is correct, then possessing the necessary physical knowledge and a concrete mental image based on it should allow it to become a spell. Therefore, something essential is missing for it to become a spell. I needed to examine exactly what that missing element was, scrutinizing every possibility.

I continued going to the mansion, observing daily life there, then returning home to diligently work on developing new magic and the echo detection device using the voice-altering gemstone.

Around the time two weeks had passed,

I began to feel the increasingly insistent gaze from maid Anne, urging me to deliver results soon.

Today, I visited Lina’s room before noon.

As usual, I maintained my maid disguise. Thanks to this disguise, I was able to speak with the other maids who worked the same lowly tasks. Within this mansion, I used the fake name Tanaka.

"Ms. Tanaka, could you please deliver food to Miss Lina?"

"Yes, of course. I'll bring it to her right away."

She was conveniently used by the unsettling employer, appearing as a helpful maid among her peers who was always willing to approach the mysterious mistress. Thanks to this, she avoided unnecessary prying, which was quite convenient.

"Still, Tanaka-san really gets close to that person often." "Maybe it's because she's the one Anne brought along, or perhaps she's just after more money."

It seemed surprisingly easy to overhear such backbiting.

As the saying goes, "Speech is the root of trouble."

"Miss Lina, your meal has been brought."

"Please come in."

As I observed her daily life, I found myself genuinely caring for Miss Lina, almost like a maid. Given that she spent her days confined within this tower, she rarely received the kind of respectful treatment befitting a lady.

Occasionally, she would dramatically act like a princess just to pass the time. It was merely a game, but given how often she was idle in her daily life, it was certainly enjoyable enough.

After finishing her meal, she began her usual prayer. Usually, she would quietly fold her hands and pray in silence. Today, however, she took out a deep blue accessory. It looked like a pendant. She had never seen one like it before.

"Today, you're using a pendant, aren't you?"

"Yes, it's a special day, so I must pray earnestly. Please excuse me for a moment."

The prayer began. As usual, she faced the altar-like shrine while reciting the sacred words. Today, she offered her prayers with unwavering devotion. I remained silent, making no disturbance.

But I couldn't believe my eyes.

I saw the pendant glowing faintly through the gap in her hands. The magic stones attached to her body were also glowing—faintly, barely at all.

This was it. This was what I’d finally found.

As I stood there stunned, Lina had quietly finished her prayer.

"Lina, I have a few questions. How did you come by that pendant? And how often do you use it for prayer?"

"What's wrong? You look so frightened... Is this...?"

Listening to her words.

Apparently, the prayer pendant has been passed down through generations, and Lina inherited it as a keepsake from her late mother.

As for what it's made of, no information is available.

She prays with it roughly once every two weeks, following a ritual. Having used it for so long, its magical reaction has weakened significantly. It's unclear what effect, if any, it still has.

I've been studying the magic stone and watching its reactions for weeks, so I was the only one who noticed.

That's probably why no one else realized it. It hurts a little, but I need to examine this pendant further.

I turned back to Linah.