Roland had long envisioned bullets for spinning gunpowder weapons, as round lead bullets and loose gunpowder were technologically outdated. Given Anna's machining capabilities, producing copper-cased fixed charges was technically feasible. The key challenge lay in igniting the black powder inside the cartridge without a reliable primer.
The primer of early metal case fixed charge bullet is usually mercury tetrafluoroacetate, which is extremely sensitive to impact. When the trigger is pulled, the impact pin is activated, and the mercury tetrafluoroacetate at the bottom of the bullet ignites, thus firing the propellant and ejecting the bullet head out of the barrel.
Unfortunately, despite his best efforts, he could not recall the exact raw materials required for the preparation of mercuric acid. Literally speaking, nitric acid and mercury must be involved. However, the handwritten reaction equation indicates that the reaction between these two substances would only produce mercuric nitrate.
Moreover, merely knowing the raw materials does not guarantee the successful production of the final product. Whether the solution has concentration and temperature requirements during the reaction process, and whether a catalyst is needed are also critical factors affecting the yield of the final product. Furthermore, due to its sensitive properties, mercuric tetraethoxysulfate (MES) is highly prone to triggering explosions during manufacturing. A single misstep could result in the loss of two fingers, which is why he hesitated to attempt it personally.
Therefore, Roland had to settle for a compromise: using metal cartridge cases while still employing the flint-and-tamper ignition method. This required the spark to penetrate the cartridge's interior to ignite the gunpowder. Consequently, the base of the cartridge needed to have a hole to allow ignition, while also preventing any leakage of the gunpowder.
Clearly, these two factors are in irreconcilable conflict: the larger the aperture, the faster the gunpowder leaks out. Conversely, if the aperture is too small, the sparks from the flint will struggle to ignite the gunpowder inside.
He needed a substance that could be easily ignited by Mars while sealing the opening to prevent gunpowder leakage.
Roland's first thought was nitrocellulose, commonly known as gunpowder.
This was one of the few chemical substances he remembered that could be used as weapons—its preparation required only simple materials: cotton soaked in a mixture of two strong acids. The most common acids were sulfuric and nitric, and their production posed no significant danger. He had initially planned to wait until recruiting alchemists before attempting to produce gunpowder, but now that the seven-day deadline was set, he decided to roll up his sleeves and take matters into his own hands.
When he mentioned the goose-feather brush, he wrote down his long-conceived idea on a scrap of paper.
The first priority is cotton—preferably thin, untextured, and undyed yarn. A significant amount of this material was brought back from the Duke's estate and is now stored in the castle's warehouse. The cotton yarn must undergo degreasing, as surface oils would impede nitration. Most transmigrators are familiar with the deoiling agent: sodium hydroxide, commonly known as caustic soda. This substance also serves as a raw material for detergents. By adding sodium hydroxide solution to the oils, mixing thoroughly, and then molding and solidifying the mixture, one can produce soap for cleaning. However, Roland has been preoccupied with developing industrial and agricultural projects and combating external threats, leaving no time to research this household essential.
The simplest method to produce sodium hydroxide is likely electrolysis of saltwater. Prince realized that to develop a new type of bullet, he must first start with a DC generator.
...
Ashes walked along the Chishui River, feeling a little down.
Ever since the witches learned her purpose was to persuade the Sisters of the Order to leave Border Town, their attitude toward her had grown cold, no longer the warmth they showed when they first met her last night.
Moreover, she observed that most witches practiced their abilities in the castle's backyard, indicating Roland had also discovered a way to avoid being consumed by the Magic Power. Her plan to exchange this vital intelligence for the witches' goodwill had collapsed. With no other recourse, she could only explain the pros and cons to them individually and persuade them to leave.
What surprised Ash most was Roland Wimbledon—his appearance remained largely unchanged, yet his every gesture exuded an indescribable charm, a stark contrast to his former image as a spoiled young man.
Why did this happen? He had always been a coward who would first think of fleeing when faced with problems. He feared taking responsibility for his own actions, let alone standing up for others. The memory of that harassment incident—just a single look of disgust from God—made him panic and collapse. When Tilly came running, he lied, claiming he had fallen accidentally, and even blamed the Fifth Princess for choosing such an ugly woman as a Guardian.
From that moment on, Ash's perception of the Fourth Prince plummeted to rock bottom.
She had assumed such individuals would be easy to handle, but today's negotiation left her completely at a disadvantage. When the opponent proposed a one-on-one duel, she realized even physical coercion would prove futile—since the other party wasn't dodging questions but was determined to confront her challenges head-on through combat. At this point, threatening him personally would only further damage the Witch's standing.
Ash sighed. If only she were as clever as Tilly—any problem would be solved effortlessly before her. If she were in such a situation, she could surely find a solution too. The ease and anticipation she had come with had vanished. If not for her determination to help Tilly as much as possible, Ash would have immediately boarded the ship bound for Bishui Harbor, eager to leave Graycastle as soon as possible.
Without realizing it, she had left the town. The opposite bank of the river was no longer a lush wheat field, but a virgin woodland.
Just as Ash was about to turn around, a surge of Magic Power suddenly came from behind. Instinctively, she tilted her head, and a dagger shot out from her cheek, slicing horizontally. The surging Magic Power had transformed into a colossal wave. Ash felt a sharp pain in half her cheek—the opponent's fluid movements were clearly beyond the reach of an ordinary person. Without hesitation, she let her body collapse completely, dodging the sweeping dagger, and propelled herself forward with a single-footed thrust.
Yet the other party vanished into thin air, reappearing behind him in the blink of an eye—so swiftly that he couldn't even see how they moved.
She drew her massive sword, spinning her body in a full circle that sent the blade whistling through the air with such force it sent dust swirling across the ground. Her all-around attack could neutralize any threat within its range, but the move faltered under the opponent's eerie agility. The massive blade swept past the shadowy figure as if it had never touched anything.
"Damn," she thought to herself, her muscles tensing as she braced for the next assault. The shadow vanished before her. Dust settled slowly, revealing the man standing nearby, his dagger in hand.
It was the nightingale.
"Is this a warning?" Ash frowned.
"Of course not," she tucked the dagger into her waistband. "I just wanted to see the Extraordinary's strength." "Is that so? I thought you meant—" "—to get you out of Border Town fast, or I'd be rude to you?" Nightingale cut in. "Then what's the difference between me and Hakkara?" Hakkara? Why mention the former leader of the Guild of the Ashes? Ashen wondered, puzzled.
"You can rest assured in persuading every sister—if anyone wishes to leave with you, I believe Your Highness won't stop you, nor will I. But..." Nightingale paused. "Don't try to harm or threaten Roland Your Highness, or I won't deliberately miss next time." She grinned and vanished into thin air. "Enjoy your life in Border Town." Ashes shook her head, as if reminding herself.