"<>?　<>?　What is the role of the <> in ......?　What is the role of the <>?"

"What?"

Jin was dumbfounded.

At first glance, this question seems difficult, but the active core is the part that activates the effect when a complex system is configured, so it has little relevance to the linkage.

When I told him this, he took some notes and opened his mouth again.

"So, what is the <>?　Please explain the <> in the <>.　Please explain."

"Uh, yes.

<

"Free magic element (ether) existing in space can be taken in by applying a equivalent to a weak to it. For this purpose, ......"

Jin explained the situation as if he were standing on a plank of water, but the supervisor who listened to him was taking notes with a look of confusion on his face.

"Well, that's all," he said.

The superintendent closed his notebook and quickly left the room.

"...... I bet he didn't understand the questions," he said. Especially his question to Jin, it was as if he was reading from his notes.

Eira muttered indignantly.

"I guess that's why he's on the advisory board. Maybe someone somewhere has been listening to this exchange."

Eira seemed to be convinced by Jin's comment.

"Well, that's a roundabout way of doing things, isn't it?

I see.

After two whole days without any news, Jin and the other three were enjoying their visit to the royal city with permission.

"I knew you had a different ...... selection, didn't you?"

"Yes, they are."

"Hey, Jin!　This is something amazing."

Jin was tired and Eira and Katya felt cold, so they switched to window shopping on the second day. Of course, if they found something they liked, they would buy it.

"Let's see ...... what's this?"

The three of them, who have been looking around mainly at tool shops, magic tool shops, etc., had just arrived at a shopping street on the main street.

"It's a little old, but it's an automata. I'd like to have one, but the price is ......."

The price listed was 3.5 million dollars, or about 35 million yen.

"Who's going to buy it? ......"

"It's half a billboard, isn't it?"

It doesn't look like it's going to move in the first place," Jin added.

Since there was no flow of magic power, I secretly it and found that the ether converter was damaged and the mana driver was missing.

Jin imagined that it was just a mere ornament, or perhaps a collector's item.

"Jin-san, what is this?"

Katya asked Jin, pointing to a magical tool displayed in another store.

"Let's see,...... ah, there are some interesting things here. This is not so much a magic lamp...... as a magic lamp stand. The design is interesting ......."

As Jin said this, a letter that seemed to be a corruption of <> jumped into his eyes.

"<>......?"

"What?"

"No, no, it's nothing. It suddenly occurred to me that it might have been made by an acquaintance of mine.

In his haste, Jin said almost verbatim.

(But well, considering it's been 400 years, maybe it's the brand of the workshop that Bina started ......)

"Jin?"

"...... Oh, what is it?"

"No, I was just wondering if something was wrong.

I was just thinking about something.

"......, what does that have to do with the name Beena?"

I don't know. I don't know.

"What the hell is that?"

Eira laughed and did not ask any more questions.

"Oh, I like this one," he said.

"This is interesting.

"It's a bit expensive. ......

Jin and the others continued to browse the stores in the city until dusk.

* * * * * *

"Well, the knowledge of the mage Jin is outstanding, isn't it?

Yes. It would be a shame to leave him here in this country.

I see. I'm contacting the home country now. You will hear back from them soon. Then you can go to ......."

* * * *

"How can we reduce friction and wear on the sliding parts?

On the third day, Jin and his colleagues had started a study session on their own initiative.

"If you rub a hard object against a soft object, the soft object will naturally wear out, right?

"Of course."

Jin made a premise and Eira affirmed it.

"Then, how about two objects of the same hardness?"

...... both of them will be reduced?

"Correct, Katya."

Jin further explained his theory.

"By the way, wear resistance is not only determined by hardness.

What do you mean?

"Wear is the process by which a material is worn away, so the stronger the bonding force between molecules, the less likely it is to wear away. But it is not equal to ."

"Well, I don't know if I understand."

Eira tilted her head,

"Then, what is <>?"

KaChea asked.

"It is the resistance of an object to deformation, the resistance of an object to damage. Resistance to deformation depends not only on the bonding force but also on the molecular structure, and resistance to damage is the very idea of hardness.

At this explanation, Katya looked at me as if she did not understand.

It was not surprising, since even junior high school-level physics was not common knowledge.

"You know, there are stones that are hard but easily worn away, right?"

"Oh, yes, there is.

"Typical of a hard stone with high hardness but low wear resistance."

......I can see why you say that.

"Adamantite is hard and not easily deformed, and is also highly resistant to wear, so it is used as a thin coating on the joints of golems.

Jin explained,

"Then it can be used for bearings too!

Eira said.

"That's right. It would also prevent seizure. It's just too expensive."

"Oh, cost-effectiveness, you mean?"

Katya nodded in agreement.

Jin thinks that these two are too good to be left in their current environment.

However, Jin himself is now rootless and looking for a way back home.

On the one hand, he wants to return to Erza and the others as soon as possible, but on the other hand, he worries about the future of the girls he has met.

(It's a difficult problem. ......)

(It's a difficult problem, isn't it?) His worries are endless.