It was a straight line of about 120 kilometers from Magiroots Village to Reinhard’s territory, Kalts Village. At a speed of forty kilometers per hour, the journey took three hours.
With Lake Tosmo visible to the left, the airship crossed over the skies of Banne and began to lose altitude. Kalts Village was situated near Ekishi, the site of Elsa’s family home.
“Welcome, Jin.”
The airship touched down in the spacious front yard of Rankenhaus, Reinhard’s mansion.
“Young lady! You look well!”
“Jii....You as well.”
Adberg—Elsa’s former butler and now Reinhard’s secretary—had been waiting to greet them alongside his master. He took Elsa’s hand, tears welling in his eyes.
Over lunch at Rankenhaus, Jin updated Reinhard and Bell on the wedding of Count Kuzuma and Beena.
“I see. Louis and Beena seem like they’ll make a fine couple.”
“Yeah. Oh, that reminds me—I caught a glimpse of the carriage you sent as a gift, Reinhard. When did you find the time to build that?”
“Haha, I managed to squeeze it in somehow or another.”
When Jin mentioned that Elsa’s Mana Overload Syndrome had been completely cured, Adberg wept with joy.
“Jin-sama, thank you for saving the young lady...!”
As Adberg bowed his head repeatedly, Elsa’s eyes also grew moist as she watched him.
The meal concluded on that warm note, just as a maid entered the room.
“Lord Reinhard, you have guests.”
“Ah, right on time. Please show them to the workshop.”
“Guests?”
When Jin looked at him inquisitively, Reinhard explained with a smile.
“It’s Toa. We’re building a desiccant plant, remember? And the plan is to develop it so it can be mass-produced for the general public, isn't it?”
Jin nodded in understanding. He had already communicated the broad strokes to Reinhard via manacam, and Toa had promised to cooperate once they reached the territory.
“Regarding the limestone, Toa came by the day before yesterday and told me he’s found a promising deposit.”
Toa had apparently arrived a few days ahead of them; he was as efficient as ever.
“The location is a rocky mountain near Lake Tosmo. Apparently, it’s almost entirely composed of limestone.”
“That’s incredible.”
As far as raw materials were concerned, the problem was as good as solved. In Japan, the mountains in the Chichibu region were famous for being made of limestone; they were constantly being excavated for cement production. One peak, Mount Buko, had been mined so extensively that its very shape had changed.
“So, I sent some men out yesterday to begin some preliminary mining.”
“Impressive. You’re really on top of things.”
Even though it was a small village, Reinhard had embraced his role as lord and was busy making arrangements for the settlement’s prosperity.
“I was just looking for a way to establish a local industry here, you see.”
It was truly a godsend, Jin thought.
“Let’s head over and get to work immediately.”
“You got it.”
“...Jin-nii and Rai-nii are both so full of life.”
As Elsa whispered this while watching the two men get worked up, Bell chimed in with a smile.
“Hehe, that man has had excitement written all over his face since last night. He’s just thrilled to be away from his daily administrative duties for a while.”
Reinhard’s cool image was somewhat undermined by that final remark.
After a brief rest, Jin and Reinhard headed to the workshop built on the grounds of Rankenhaus.
“Hello, Jin-kun, Reinhard-dono.”
“It’s been a while... though I suppose not that long.”
Toa usually addressed Reinhard with “-kun” as well, but in this setting, he used “-dono” out of consideration for the household staff.
Stearena was also present, unusually dressed up. Her copper-colored hair was tied up high, and she wore a light purple dress that reached her ankles, paired with a white, summer-weight cardigan. Apparently, she was on her way back from paying her respects to House Theoderic, the family of Toa’s late wife.
Stearena mentioned she was going to have a chat with Bell and left the workshop.
“Toa-san, finding that limestone deposit... you’re as reliable as ever.”
Toa scratched his head at Jin’s praise.
“Well, collecting materials was part of my original trade, after all. I have a fairly good grasp of the resources within this country.”
He truly was a top-tier alchemist.
“Right then, I’ve prepared the materials here,” Reinhard announced.
He had gathered limestone, magi-crystals, and various stone samples to be tested as furnace materials.
“I heard you used a carbon crucible for your initial experiment?”
“Yeah. But that isn't practical for mass production. We need a common material that can withstand eleven hundred degrees Celsius.”
In modern science, ceramics, superalloys, and carbon-based materials had been developed as “ultra-high temperature materials” for fields like aerospace and energy. Here, however, they were limited to what was available.
“Toa explained the production method to me. The principle is simple enough, but the challenge is finding a way to mass-produce it using standard methods, right?”
Due to his overwhelming aptitude as a Magi Craft Meister, Jin’s perspective often drifted away from that of the common man. To bridge that gap, he was relying on Toa’s expertise.
“When it comes to general fireproof materials, we usually look at these types of rock,” Toa said, pointing to the stone samples.
“First, we have tuff.”
Oya stone was a member of this family; it could maintain its strength up to about a thousand degrees Celsius. However, that was slightly short of the eleven hundred degrees required for calcining quicklime.
“Then there’s sandstone.”
This, too, was only viable up to about a thousand degrees.
They looked at andesite and serpentinite as well, but none of them appeared capable of withstanding the necessary heat.
“Hmm. We’ve hit a deadlock right at the start.”
“It’s going to be difficult to turn this into a village industry if the equipment is this specialized.”
Jin and Reinhard both held their heads in their hands.
“Carbon, zirconia, or platinum would work perfectly, but...”
Using such expensive materials would make the industry financially non-viable. As Jin and Reinhard struggled—a rare sight—Elsa watched them with a pained expression.
“...Are there no other heat-resistant stones...?”
Jin desperately combed through his memories.
“Heat... a furnace...”
When he thought of industrial furnaces, he still felt a faint tremor of dread. A small crucible was one thing, but a furnace large enough for a person to fall into... the mere thought made his skin crawl. It was a natural reaction; he had once lost his life falling into the ladle of an electric furnace in his previous world.
It’s not like I’m afraid of fire or flames, Jin thought, feeling more than a little sheepish.
Elsa, noticing his shoulders trembling, remembered the circumstances of Jin’s past and reached out to gently take his hand.
Perhaps it was her support that cleared his mind, for Jin suddenly remembered a specific material.
“Peridotite.”
It was a type of rock primarily composed of olivine—also known as peridot. It was a plutonic rock formed deep underground and possessed exceptional heat resistance. The melting point of olivine was as high as 1910 degrees Celsius, and sand made from crushing it was often used in industrial sand-casting.
High-quality olivine could be mined at the Inado Mine near Kaina Village, but that was gem-grade and far too expensive. However, if they could find common peridotite, it would make an ideal material for the furnace.
“Peridotite, huh...”
Peridotite was an igneous rock, meaning it was volcanic in origin. This put its typical locations at odds with limestone, which was a sedimentary rock. The Shouro Empire was primarily composed of sedimentary terrain, especially the region surrounding Lake Tosmo. While andesite could be found nearby, there were no mountains known for peridotite in the immediate vicinity.
“If we have to import heavy stone from far away, the shipping costs will kill the profit margins,” Toa noted.
As someone who had once spent a fortune on his own material collection, Toa kept a sharp eye on the bottom line.
“Hmm...”
Jin sighed, feeling the full weight of how much of a “cheat”—how utterly unfair—Hourai Island and magic truly were. If they at least had the raw materials, he could justify using magic to process them, but without even that, they were stuck.
“Would iron not work?” Toa asked.
Jin shook his head. “No. In terms of melting point alone, it would be fine, but if you heat iron to such high temperatures in the presence of air, it oxidizes rapidly and crumbles to pieces.”
Iron’s affinity for oxygen was high, and heat only accelerated the reaction.
“This is proving to be unexpectedly difficult,” Toa muttered, crossing his arms in thought.
“Does that mean we have no choice but to use a barrier to contain the heat...?”
That would drive up the initial costs and make maintenance significantly more complex for the villagers.
“I’d like to keep that as a last resort,” Jin said.
As the group sat there racking their brains, a figure peeked into the workshop.
“What’s everyone up to?”