After the meeting, Roland left Barov alone.
"You've seen the numbers," Prince declared bluntly. "Chemical labs are hiring, Graycastle Industries needs workers, and I'm planning mass production of soap and perfume – all requiring massive manpower. Once most townsfolk pass basic education exams, we'll have at least six to seven hundred people by next year. That's still far from enough. We need more people." "If we recruit from the fortress..." "No," Roland interrupted. "After the city's construction next year, the fortress will merge with the town. It's like transferring resources from one pocket to another. We need more people from beyond the Western Frontier." "This..." Barov hesitated. "It's not that simple. Recruiting from other cities won't be easy – local lords won't stand idly by." "Let's skip the cities," Roland said, dipping his finger into ice water. "Have you noticed how Graycastle's been in turmoil since the Demon's Moon? Tifeck's repeated attacks on the South destroyed Eagle City, leaving surrounding villages in ruins. Then there was the Northern Expedition that stripped Duke Ace of his title and lands for treason. Finally, the Eastern Sea Raid..." He slammed the table twice, leaving a puddle of water. "The Sea Breeze County, Golden Ear City, and Raven Castle all suffered. The surrounding towns? The sheer number of refugees fleeing to the capital alone speaks volumes about the devastation." "You mean..." Barov's face showed a thoughtful expression.
"Promote the Western Frontier," Prince smoothed out the water. "For the past six months, only the Western Frontier has remained peaceful—no forced conscription, no war ravages. The first point—Tifico's extensive use of civilians in combat—will inevitably lead to recruitment and even looting of civilians across regions. No one can guarantee they won't face such consequences themselves next time. That's why a safe haven isolated from warfare is our key propaganda focus." "I understand," he mused. "You're planning to attract civilians from other towns and villages through promises of no forced conscription, no forced labor, along with housing, food, and stable jobs?" "Pretty much," Roland nodded with a smile. The Minister's Assistant's sharp thinking and quick learning were always his strengths. "We should also emphasize the generous benefits for literate individuals. I believe some desperate Knights and Nobles from these areas will be willing to venture to the Western Frontier for a chance." Whether villages or towns, most were territories of lesser Nobles. In peacetime, even barren land and poor farming could sustain a few acres to feed the population. But during turmoil, severe population loss would make survival difficult. A safe haven would appeal to most people—after all, their territory wouldn't be seized even if left unattended. Once this period passes, they could return with money and mercenaries to reclaim their lands.
As for how to promote it, he believes the other side has its own way.
"But Your Highness, this would incur additional costs for resettling these people, and we can't afford to halt grain imports," Barov hesitated. "Should anything happen to the caravan, the town treasury could dry up in no time." "Well... you've got a point," Roland stroked his chin. For a nascent political force, the most crucial task was to build public trust. If they suddenly faced a payroll crisis, the promising situation would turn sour. "Here's the plan: You return to finalize the proposal, and we'll proceed once the caravan completes next month's trade with the town and the treasury is replenished." "Understood, Your Highness," Barov murmured, placing his hand on his chest.
After wrapping up his work, Roland returned to the office and began brainstorming ways to fulfill Margery's balloon order.
A thousand golden dragons cost more than a steam engine, yet their production was far cheaper. The airbags were primarily hand-painted by Soroya, while hemp ropes and bamboo baskets were inexpensive materials. In fact, Roland had already created a simple prototype in the armory courtyard: a hydrogen balloon capable of carrying both Lightning and Maxie into the sky simultaneously.
After careful deliberation, he ultimately abandoned the hot air balloon concept. The required gas had to be produced through coal carbonization, the equipment was space-consuming and cumbersome to manufacture, and coal had to be imported from other towns. Small-scale production proved highly unprofitable and far less convenient than hydrogen, which is readily available.
The prototype was fabricated with a single-layer water-based coating, where the backing paper was burned off after painting. This design made the entire balloon nearly weightless while maintaining exceptional flexibility. During testing, the inflated balloon withstood rain, impacts, and fire without damage. Even when pelted by various birds, Maxi remained unscathed—only an iron needle could barely pierce its millimeter-thick coating. Thanks to its ultra-lightweight nature, a hydrogen balloon with a diameter of about five meters could carry an adult into the sky.
The only difficulty is how to solve the problem of filling high pressure hydrogen cylinders.
The DC motor used for electrolysis of water to produce hydrogen must not be sold. Connecting a single motor to a steam engine would allow inflation of all hydrogen balloons, which is clearly not cost-effective. To continuously earn Golden Dragons from the big dog owners, high-pressure gas cylinders capable of repeated inflation must be available.
The cylinder itself isn't particularly challenging. If the material isn't up to standard, we can reinforce the walls using either cast iron or wrought iron. With Anna's expertise, precision machining is no issue. The real challenge lies in the inflation process—modern gas cylinders operate at pressures exceeding 20MPa. Relying on a simple air pump would be a pipe dream, even with ten Kirin arms (a mythical creature's arms) at its disposal. At the very least, a high-pressure pump is required. Moreover, without sufficient internal pressure, the hydrogen balloon simply can't be inflated.
High-pressure air pumps are categorized into piston compressors and turbo compressors. The former belongs to the internal combustion engine technology tree, while the latter falls under the turbine category. Developing either type is a time-consuming and labor-intensive endeavor. By evening, Roland had finally devised the simplest solution: self-pressurizing within the cylinder.
The inspiration came from a news report he had seen before his time travel: street vendors selling hydrogen balloons used modified liquefied gas cylinders to store hydrogen, which resulted in an explosion and a tragic accident. The cause was that the vendors directly reacted dilute sulfuric acid with aluminum inside the cylinders to produce hydrogen without calculating the reaction volume, leading to excessive pressure inside the cylinders, which directly caused the cylinders to burst.
The self-inflating method involves filling the bottle with dilute sulfuric acid and a reactive metal to displace hydrogen. While zinc is commonly used in laboratories, aluminum produces the most hydrogen per unit weight. However, neither material is available today. Therefore, Roland still plans to use iron for the reaction—Lucia can isolate extremely pure elemental iron. The slow reaction rate at room temperature can be improved by heating and increasing contact area (e.g., using iron sheets or powder). An inner coating can also prevent corrosion from the acid solution.
At this point, he immediately sketched a simple diagram on paper— to minimize air leakage, the high-pressure cylinder should be as integrated as possible, with the body forming a seamless unit. Only a protruding threaded opening at the top allows the valve-equipped nozzle to be screwed in.
After injecting the reactants through the opening and tightening the gas valve, the continuously generated gases have nowhere to go, allowing the pressure inside the bottle to reach a remarkably high level. During use, simply unscrew the valve, and hydrogen gas will gush out, filling the airbag. The refill process is equally straightforward: remove the gas valve, dry off any moisture, and clean out the ferrous sulfate crystals inside before refilling the reactants.
Given that dilute sulfuric acid is also an alchemical product, its inflation price cannot be set too low.
Roland figured, 'Just set it at fifty gold dragons per charge, and send it in ten charges.'