Three days have passed since we officially accepted Reinhard, Bertsch, and Saki as our Horaijima family.

Needless to say, they are enjoying their time together.

Reinhard has completed the outer boat that he had wanted to build for a long time, and Saki has increased her knowledge of various materials.

Erza was gaining experience by making vacuum cleaners, refrigerators, lighters, popcorn makers, distillers, magic lamps ......, and other magical tools that Jin had seen and made before.

What was Berche, who was neither a magecraftsman nor an alchemist, doing? She was learning and expanding her repertoire of cooking under the tutelage of Peridorider, a five-colored golem maid.

Edgar, Aal, Neon, and Noir did not just sit still.

Edgar learned from Lao Tzu, Aalu from Butler 1, Neon from Soleil and Luna. And Noir was learning a lot from Rand 1.

"Hmmm, Jin, the development environment here is great!"

Reinhardt said happily when he came back from testing an ocean-going ship in Tatsumi Bay. For now, I've asked Marine 50 and 51 to drive the outer-wheelers.

"I don't think I'll be satisfied with a regular workshop anymore. ......"

Reinhard mutters with a bitter smile. He spends most of the day in the workshop, but in the evenings and at night he is dragged along by Bertsche and seems to be taking a proper rest.

"Reiko, can you help me with something?"

Elsa seems to start something with Reiko again. Lately Reiko has been consulting with Elsa from time to time, and Elsa has been relying on her.

"Yes?"

"Well, this time I'm thinking of making accessories instead of magic tools. ......"

"Okay, a design."

Reiko has in her memory, via the old man, information about various parts of the world that the fifth column (Quinta) has studied.

Among them were the designs that were popular among the noblewomen.

"Jin, may I have a word with you?"

Saki sees things from a different point of view from that of Jin and other magecraftsmen, which Jin finds interesting.

Saki wears a white coat. Jin made it as a gift from a cloth woven from the threads of a ground spider. It is stain-resistant and durable.

She looks like a mad female researcher. The glasses suit her too well.

"Yes?"

"Yes, it's about engineering magic. What exactly is engineering magic?

"Hmm?　......, right, the magic used in magecraft, right?

It was a very obvious answer, but it did not satisfy Saki.

"No, no, that's not what I want to ask you...hmmm...let's change the question then..."

Saki opened her mouth as she looked out the crystal window.

"Jin, Erza, Reinhardt and the other Magi craftsmen can use the magic of <>, right?"

"Yes, that's right. That's because it is engineering magic.

With Forming, even adamantite can be processed, right?

Yes.

Adamantite is the hardest metal known. It's non-interacting with magic. If it can change its shape, then it must be very powerful magic.

"So that's what you're saying. ......"

Jin understood what Saki meant.

For example, bending adamantite requires tremendous power. But the magic of forming makes it possible with a little magic power. Why is that?

"Well, I hadn't really thought about it that much. ......"

Jin also has a hypothesis about magic. I put it together again in my mind and decided to explain it.

"I heard that deformation (forming) works on the atoms and molecules of matter, weakening their bonding power and then changing their shape."

"I don't understand, but does it mean that once the material is softened, it is reshaped?"

Saki did not seem to understand the meaning of atoms, molecules, and bonding force, but she seemed to grasp the concept.

"Then, in a sense, isn't transforming (forming) one of the most powerful magic?　Swords, armor, and even castle walls are useless if they are transformed, aren't they?

"Well, it doesn't work that way. First of all, the surgeon must be able to touch it with his hands. And the size of the object that can be processed is proportional to the magic power of the magician.

"Hmmm...so you're saying that the more contact required, and the larger the object, the more magic power is needed."

"Yes, and it takes a little longer to activate. And it takes a little longer to activate. You have to touch it, let the magic power flow through it, and then change its shape. This procedure is troublesome. It's not like releasing fire magic.

With the exception of Jin, it is impossible to bend a sword that has been slashed by a normal sword by forming. Also, it is impossible to make a passageway by forming the castle wall due to the amount of magic power.

"I see. I understand now. Thank you."

Conversations like this were often exchanged.

That was on the first day. And on the second day.

"Jin, is it true that engineering magic does not work on living things?"

This was another question from Saki.

"Yes, it is true. For example, shaping does not work on standing trees. For example, shaping does not work on standing trees, even though it is possible to cut them down with a wind cutter.

"Then, at what point does shaping start to work?　Can you do it once you cut it down?

"Yes, you can. Yes, it can be done. Branches and trunks can be processed by shaping once they are cut off.

Hearing Jin's answer, Saki turned her head down and thought silently. After thinking for a full minute, she looked up.

"Let's put aside the line between standing timber and lumber for the moment. I'll just leave the line between standing timber and lumber for now. ...... Then, why can't we do shaping on standing timber?

Now it was Jin's turn to ponder. However, Jin came up with a hypothesis in less than 30 seconds.

"I think that shaping and the forming that was talked about the other day are not done by mana, but by free magic element (ether).

Every living creature in this world has mana without exception. They take in free magic element (ether) and change it into mana in their bodies.

It is said that mana circulates in the organism. Jin presented his own theory that engineering magic would not work as long as this mana is circulating in the body.

"Wow!　That's great, Jin!　That's a totally new theory!　Then, to become a Magical Engineer (Magi Engineer)...... or a Magical Craftsman (Magi Craftsman), one must be able to manipulate free magical element (ether) or not!

And so it goes.

What about Saki on the third day?

"Jin, I have an idea for an interesting experiment. Will you help me?"

Saki made such a proposal.

"What is it?"

Saki always has interesting ideas. Jin waited for Saki's explanation, hoping inwardly that it would be interesting this time, too.

"I was wondering if you could dissolve the threads of the ground spider.

"What?

The threads of the Grand Spider are extremely strong and tough. However, while the threads are easy to use, they are limited in their uses.

"I see. ......"

There is a resin called nylon. To be precise, it is a polyamide resin. <

Polyamide resin is used not only as a fiber but also as a plastic, which is the original use of resin.

"You're asking if we can use it as a natural resin. I hadn't noticed that."

Jin is very enthusiastic.

"The threads of a ground spider are ineffective against ordinary magic, aren't they?

Saki's question was right on the mark. The threads of the Grand Spider do not burn or melt even with the highest level of fire magic.

"You said that the Grand Spider feeds on free magical element (ether), didn't you?　So, it is safe to say that the Grand Spider is a mass of free magical element (ether), isn't it?"

That's what Jin thought, too. Since he grew up with only free magical elements (ether), his body must be made of free magical elements (ether).

"Father, Luna told me that she once examined a dead ground spider.

Unexpectedly, Reiko brought me an unexpected piece of information.

"I heard that ground spiders have a very long life span, but there was an individual that was crushed when the hole it was using as a web collapsed. He brought them home and examined them to see if they could be used as materials.

"So, that's it!　Now tell me what's next!"

Saki rushed to him with great vigor. Reiko continued her explanation without being influenced by Saki.

"According to this, 80% of her body contained free magic element (ether).

Persica of Horai Island also contains a large amount of free magic element (ether). The same is said to be true of the ground spider.

"It might be a similar analogy to say that free magic element (ether) changes its form and becomes a thread.

Jin says so, and Saki agrees with him.

"That's a strong possibility!　The fact that it is inviolable by ordinary magic also confirms it, doesn't it?

The two realize that they are going a little off-topic here. Originally, the story was about melting the threads of a ground spider.

"Well, it's fun to discuss with you, Jin. I got carried away."

"Well, you mean dissolving the threads of the ground spider, right?　<, it should be possible. Reiko, bring me some of the Grand Spider's threads. Scraps of cloth will do.

Yes, Father.

Reiko brought some scraps of cloth from when she made Saki's lab coat.

Wait a minute. ...... umm... do this here... and ...... okay, <>. <>"

Saki was startled to see Jin who had modified the fusion into the original dissolute, but she managed to restrain herself and looked at the act of melting the threads of the ground spider, which was the most important issue at the moment.

The melted threads of the ground spider were translucent, and Jin stretched them into a flat sheet by forming.

"You did it, Jin!

"Yes, it worked."

Saki was so happy to see that his idea had come true. And Jin was happy to have found a new possibility for the Grand Spider's threads. Saki and Jin were excited to see each other.

* * * * *

Finally, I would like to add a few words.

"Jin-sama, I'd love to have this bathroom in my house!

"Jin, Jin!　That toilet is a good one!　I'm going to have it installed as soon as I get back home!"

About two more people were fascinated by the toilets, which were equipped with deodorizing, sterilizing, and decomposing functions in addition to the hot-water washing toilet seat.