"Oh, I can use this."

Jin receives a rubber tire that has been delivered. It is not a wire, but seems to have a linen cloth in it. It is similar to a bias tire.

The surface of the tire has a block pattern on it, indicating that it is an extension of a bicycle tire.

"Is this as you instructed?"

After the work golem returned to the factory, the factory manager's automaton came in and asked how it was done.

"Yes, it's good. What about the ...... price?"

Although he had been told by Chief Hiro that he would not be asked to pay for his work, Jin, who was not a Mitsuho resident, asked just to be sure.

"Yes, you don't have to pay for it.

And the answer was as expected.

（I wondered what kind of person he was (Mags ......).

It must take a lot of expertise to be able to set up a system like this.

"Father, you are going to install this in a car, aren't you?"

Reiko holds two tires under her arm. It is quite a surrealistic picture.

"Yes. Get the jack out of the car. ...... Oh, we didn't have a jack."

So, she orders a jack from the factory manager.

To my surprise, the <> worked.

Jin guessed that they must be used for maintenance of rickshaws and carts, as there are rickshaws and carts.

The jack was ready in about 30 minutes. After receiving the jack, Jin observed it.

"Oh, Oniichan, this is how this part lifts up when you turn this screw, isn't it?

Hannah, who peeked in from the side, described the structure of the jack with precise expressions, which impressed Jin even more.

(You don't have to decide on Hanna's aptitude yet, but if you educate her properly, she might become a great scholar. ......)

) Jin showed his brother's foolish side.

Now, we set the jack under the car and mounted the tires.

Since the car has a ladder frame, the jack is naturally set right under the frame.

Turning the handle, the wheels are lifted up.

When the wheels are lifted off the ground, the mud and other dirt on the wheels are cleaned off, and new tires are mounted on top of them.

Since it is not a rim, the only way to do this is to cover it from the top.

This is done in four places.

The diameter of the wheel becomes a little larger, but there is no problem because there is enough driving power.

Jin is planning to modify it in the near future, but for today, he has only applied < to it.

"Okay, that's it. Hannah, let's go back to town."

"Yes!"

Reiko drove and the car started to move.

"Wow, it's different after all."

The slight vibration that no amount of suspension, dampers, and seat cushions had been able to eliminate was gone.

Even though it was only 5cm, the effect of the rubber tires was outstanding.

"Reiko, please increase the speed a little more.

They increased the speed to about 20 km/h, confirmed that the vibration had been improved, and headed back to the guest house.

"Jin, welcome back.

Saki, refreshed after sleeping twice, greeted Jin and the others at the entrance hall.

"Where's Erza?

"She's waiting in her room. I was just looking around the garden.

The garden here is a Japanese-style garden, which is called a kaiyushiki.

There are other types of gardens such as , , and <, each of which has its own way of appreciation.

Kaiyushiki gardens are, as the name suggests, designed to be enjoyed along a promenade.

However, it was not created by a professional gardener or a famous tea ceremony master, so it is only a <> at the top of the list.

Still, it was nostalgic enough for Jin and interesting enough for Saki.

"Brother Jin, Hannah, welcome back.

When he returned to his room, Erza was waiting for him.

"I just got a call that Hiro-san will be here at 1:00 p.m." she said.

"Oh, about the inventory. Saki, what have you decided?

"I'm interested in mercury and alum."

I'm interested in mercury and alum," I thought Saki would say.

"Alum is fine, but be careful with mercury, okay?　That's what I'm going to tell you too, Hiro-san."

"Yeah, I know. Elsa has been threatening me a lot. About mercury poisoning.

That's good.

So, what are you going to do about Jin?

Jin seemed to think for a moment,

"I'm going to use this tap and dice."

"Heh, what's that?　What's that?" "It's not a material, is it?"

"Oh. This is a tool to make <>."

A tap is a tool to cut (make) a female screw and a die is a tool to cut (make) a male screw.

There was one more thing that surprised Jin at Mitsuho. That is the existence of .

Since Jin himself has access to engineering magic, he often uses or to fix parts.

However, in Kogun and other places, nails were used for wood and rivets for metal, and wedges were used for fastening.

Even for drilling holes in factories, , which are similar to metal drills in modern Japan, were used instead of .

Jin would like to promote the use of screws in Kogunkuni and other areas in the future, but if the standard differs from that of Mitsuho, it will be troublesome later on, so he thought it would be a good idea to match the Mitsuho standard if it can be done.

"It was terrible to mix inch and millimeter standards. ......"

Even today, some people may have a hard time when they build their own PCs, because many of the parts made in the U.S. are in inches.

As a side note, for some reason, the screws attached to the tips of folding umbrellas and the like are the same standard as those used for camera tripods.

Jin explained the to Saki and Elsa.

"So, by combining the spiral grooves and threads, you can tighten and secure parts?"

"...... but won't it come back?"

To this Hannah replied for some reason.

"You know, there's a thing called "masatsu" that won't loosen easily.

Elsa and Saki were surprised, but so was Jin.

"Hannah!　Where did you get that?

"I read about it in a book I read at the library yesterday.　I've read about it in a book I read at the library yesterday.

It seems that Hannah's knowledge has reached a considerable level.

(......<, huh? I wish I could do that.)

The magic to send knowledge that No.600012 used on Nidaburu. Then it should be possible to transfer knowledge without using <.

However, the composition of the magic was not told to Jin.

(Maybe No.700672 knows it. ......)

Jin, who is careful not to rely too much on the magic, did not ask, but there is a good chance that he would know it.

(Use it only where you use it, or take Hannah with you instead of teaching her. ......)

"Jin?　Jin!"

Saki's voice brought Jin back to himself.

"Oh, oh, sorry, I was just thinking about something."

"Oh, I'm sorry, I was just thinking about something. Let's go have lunch soon, shall we?

Saki said that she would like to have lunch a little early if Emir Hiro would be here at 1:00 p.m.

"...... Actually, I'm just hungry because I didn't eat much for breakfast."

"Erza!　I'm not that ...... hungry!"

Saki was upset,

"I'm hungry, too."

Erza came out as well, and Jin couldn't help but laugh.

"Okay, let's go to the cafeteria then."

Since I had never had lunch at the guest house before, I did not know what was on the lunch menu. That made it all the more exciting.

Jin and the others all headed for the dining room.