With a clear path to sourcing the most troublesome component—the water pipes—the rest of the discussion progressed smoothly.
"As for the water purification plant, perhaps we can start small and simply increase the number of identical units."
"Indeed. We can handle it through parallel processing."
Jin had felt that setting up a massive facility right from the start would be impractical, and the other members of the Jin Family seemed to share that sentiment.
"That leaves the water source, right?"
Jin had already been giving that matter some thought.
"It goes against the natural incline, but our best bet is likely setting up a water purification device along the coast and pumping it inland."
"I see. So that's why you mentioned a water delivery pump."
Even in the mountain huts of modern Japan, water was sometimes pumped all the way up from ravines to the ridges.
When sucking water up, atmospheric pressure imposed a strict limit of one atmosphere, but when pushing it up, no such limiter existed. It all came down to the strength of the hoses, the pipes, and the pumps.
Naturally, that assumed having the power source required to operate them in the first place.
"If we use magic circle pumps, we can keep the costs down."
"Mm, I agree."
"Cost is a huge issue after all, Onii-chan."
Elsa and Hanna also considered keeping costs low a top priority.
As the discussion drew toward its close, Jin moved to summarize.
"So then, we build a water purification plant by the sea and lay out takemodoki pipes leading inland from there."
"Yeah, that should work fine....And then we build an intermediate reservoir roughly every kilometer to store the water."
Reinhard added to the plan.
"We'll arrange it so the water in those intermediate reservoirs can be used for irrigation as well, right?"
Hanna asked to make sure.
"That's the idea. We'll install water purification magic circles in the reservoirs. The pumps will be magic circle types designed to constantly deliver a fixed volume of water. Of course, they can be stopped as well."
Jin pondered whether it would be better to carry this out in cooperation with Avalon, or to handle it directly alongside Deus Ex Machina.
"Jin and Deus Ex Machina... which means Hourai Island taking the lead. I think that would make managing the schedule easier."
Elsa advocated for Hourai Island taking charge.
"Yeah, I think so too. Couldn't Avalon just handle some other form of assistance?"
Saki also seemed to agree with Elsa's opinion.
"If that's the case, what will you do about the compensation, Jin?"
Marcia cautioned him.
"You always go overboard, Jin."
"Ugh... I can't argue with that."
Chastened by Marcia, Jin thought about what to request as compensation for the job.
"I don't need money. We have more than enough food....Is there anything else?"
Rodrigo was the first to offer an idea.
"How about asking them to share some of their soil?"
"Because the soil is fertile and could be useful, you mean...?"
Furthermore, if they limited it strictly to the soil excavated during the construction of reservoirs and the laying of water pipes, it would likely have little impact on the future expanse of arable land.
"However, they'll probably tell you that's far too cheap."
"Well, true..."
Beyond that, there was nothing in the Principality that Jin actually wanted....Or so he thought.
"Are there any interesting plants around, Saki?"
"Kufu, passing the ball to me, are you?...Well, there is something, if you want to call it that."
"What kind of plant is it?"
"It's a type of grass growing in the wasteland, but it seems to be a plant transplanted from Planet Hehl."
"Oh?"
Jin replied that this was news to him.
"Kufu, of course it is. I only just discovered it the other day using the Peeper, so I haven't even seen the real thing with my own eyes yet."
Saki scratched her head.
"Still, it's a useful plant. It seems to produce high-purity hydrocarbons inside its body."
"Hydrocarbons...?"
A hydrocarbon was a compound made of carbon and hydrogen. A simple example was CH4, methane. In addition, polyethylene was expressed as (C2H4)n.
When the carbon count was low, it remained a gas, but once it reached five carbons—pentane—it became a liquid.
Propane gas and benzene were also part of the hydrocarbon family.
"It's ethylene, Onii-chan."
This time, Hanna chimed in to explain.
Ethylene was C2H4.
Belonging to the hydrocarbon group known as alkenes, it was also a type of plant hormone.
For instance, ethylene was known to inhibit sprouting in potatoes.
"In other words, it can serve as raw material for magi-resin?"
"That's right."
"And what's more, it has a high magi-isotope content!"
Hanna suggested that this might be because the Progenitors brought it over from Planet Hehl.
If so, it was well worth stockpiling on Hourai Island as a material or raw resource.
Magi-resin was a substance in which standard carbon and hydrogen were replaced by magi-isotope carbon and hydrogen.
Up until now, they had been processing magi-resin artificially, but if this plant could be utilized, further mass production would become feasible.
The advantage of magi-resin over standard polyethylene lay in its extraordinarily high weather resistance, alongside its exceptionally high decomposition rate.
While these properties might seem contradictory at first glance, that was precisely what made magi-type materials so fascinating. In essence, reinforcing the bond through free ether increased its weather resistance, whereas weakening it allowed it to decompose easily and return to the earth.
"The fact that it's unlikely to cause environmental pollution is great."
Just like ordinary polyethylene, its solvent resistance was also high. Since it did not absorb water, it could even be used as a coating material for ships.
"If we impregnate takemodoki with this, we might be able to create something even better, but..."
Jin voiced the sudden thought, only to be shot down by Saki.
"Ah, for the time being, the cost wouldn't be worth it."
"Is that so? What a shame."
"Kufu, still, I'd like to bring down the cost in the future."
If demand increased, the cost would fall, but for now it was a material virtually monopolized by Hourai Island, meaning external demand was zero.
"Still, wouldn't they find it strange if we asked for weeds that they consider worthless?"
"Ah."
At Marcia's words, both Saki and Hanna made faces that showed the thought hadn't even crossed their minds.
"...Well, taking the grass is fine, but in the end, it still comes down to being far too cheap as compensation, doesn't it?"
Jin gave a wry smile.
"Compensation is tricky."
"...Indeed it is."
Every member of the Jin Family present nodded in agreement.
"We can hardly ask for their underground resources, either."
Jin remarked that those would be indispensable for the Principality's future development.
"Speaking of resources..."
Hanna spoke up, acknowledging she was straying slightly from the topic.
"It might be a bit of a tangent, but since we're out here conducting surveys anyway, I think it would be a good idea to investigate the underground resources of the Four Principalities while we're at it."
"You're right. Compiling that into data would be quite useful."
Jin agreed with her proposal as well.
And so, the distribution data of the underground mineral resources across the Four Principalities came to be fully mapped out.