Four days later, the caravan ships hoisted their sails and sailed away from the dock.
Tasa and a hundred soldiers from the First Army set sail for the capital.
Recently, Roland and Margarita reached an agreement: Tasa could withdraw any amount of Golden Dragons from her shop, with the fee deducted from the steam engine's sales revenue. Additionally, Roland was required to pay an extra 1% interest.
This time, the saltpeter and ore ingots he brought were nearly double the amount from the previous trip. Even with the deposit for converting two inland river boats, Roland still managed to collect over 2,200 gold dragons. This was an unimaginable figure during the Evil Demon's Month—selling the ore for a month would barely yield 300 gold dragons.
After the caravan departed, Maxie also entered a period of temporary absence from Border Town.
Under the agreement with Ash, she would journey to the Fjord Islands to deliver news of the western frontier.
Roland wrote a detailed letter to her, expressing his willingness to collaborate and requesting the Fifth Princess to send auxiliary witches to assist him. In the letter, he addressed himself not as a brother but as the Lord of Border Town and the Governor of the Western Frontier. Though the princess's agreement seemed unlikely, he decided to try—after all, a few more words wouldn't cost him much time.
The farewell ceremony was held in the castle's backyard, where all the witches had gathered.
The Nightingale gave her a small bag of dried fish flakes; the Lightning sent a packet of pepper.
The other witches approached with bittersweet expressions, stroking her feathers and embracing her as if bidding farewell—such was the solemnity of their parting.
"Don't worry, Goo!" she said, lifting her head. "I'll be back soon, Goo!" "What if Tilly doesn't let you come back?" Lightning said anxiously.
"Chirp..." The dove tightened its neck, pondering for a moment before wagging its tail. "Then I'll sneak back and chirp!" "We've made it clear," the young lady vowed earnestly. "If you return, I'll personally gather a flock of birds to roast for you. And we'll clear out that honeycomb we found last time when you arrive." "Chirp!" She nodded repeatedly. "We agreed, chirp!" What more could she say? Roland stood by, overwhelmed with emotion. In just a month, she'd completely won over Maxie. Well done, Lightning!
"Then, goodbye, everyone!" Maxi spread her powerful wings, took a short run on the ground before slowly ascending. After circling twice, she gradually disappeared in the southeast.
She'll make it safely, I suppose," Roland murmured, watching her slow movements, his heart racing with concern.
"No problem," Lightning said without hesitation, tilting his head. "Should...?" After seeing off Maxie, Roland quickly dove back into his hectic daily grind.
This time, he was tasked with creating a complete set of design blueprints for the two vessels left by the Xianyue Bay caravan to be retrofitted—these ships would go on to become the world's first steam-powered paddle wheelers.
The single-power-source design eliminates the need for a gearbox, allowing direct connection between the steam engine's drive shaft and the propeller. Multiple intake pipes regulate steam flow to control speed. To slow down or stop, simply close the intake pipes, letting excess steam escape through the exhaust port while the furnace continues to burn. This design also makes it easy to accelerate again when needed.
The principle wasn't complicated, and Roland quickly sketched a rough model. To get precise construction blueprints, he still needed to measure the exact dimensions on-site.
At this moment, Anna walked into the office holding a book.
"What's wrong?" He put down the quill pen and couldn't help but smile.
"The book is finished." She placed the book on the desk—it was the same one, "Fundamentals of Natural Science Theory."
Roland's smile froze instantly. Was this really possible? How could someone have read through all the high school-level math and physics in just a few months? He didn't ask if she understood, because if Anna had finished, it meant she grasped it completely. Otherwise, she would have kept rereading or come to ask him.
"Are these blueprints you're drawing meant to replace sails with steam engines for ships?" Anna's attention was quickly drawn to the sketches on the table. "But..." "What do you mean?" "Those two wheels look like oars, don't they? They generate thrust when turned, but half of them are exposed, which means some power is wasted. Why not bury them completely underwater?" "..." Roland froze, speechless. Could someone truly know everything at birth? Was she making that judgment based solely on this fleeting impression? Suddenly intrigued, he asked, "So what's the better solution?" Anna pondered for a moment, then picked up her pen and began sketching on the paper.
Roland propped his chin, watching her intently draw with evident fascination—the fringe slipping from her hairpin swayed with her movements, her slender lashes fluttering occasionally, and her fair cheeks glowing with natural radiance. Though the angle revealed only her profile, the light cast a perfect, gentle curve from her nose to her chin and down to her neck.
"Would you like some fish fillets?" Nightingale leaned in, her hand slipping between their bodies.
"Um," Anna nodded, taking the snack from him. "Thanks." Roland, whose gaze had been blocked, cleared his throat and shifted his eyes back to the paintings on the table.
Initially, Anna attempted to position the Minglun horizontally and fully submerged in water. However, this would make it difficult to spot the rudder wheel when the boat docked, potentially causing collisions with the pier or quay.
Then she installed the Minglun at the stern—a common practice, though the transmission system was far more complex. After all, the bulky steam engine was ill-suited for the stern, as the drive shaft and gearbox would occupy a significant portion of the hull space.
When Roland saw the new blueprints she had drawn, he couldn't help but marvel at her sharp mind once again.
The sketch Anna was contemplating was nearly a full-scale single-propeller design, with the steam engine positioned at the hull's base. A drive shaft emerged below the waterline, terminating in four square blades that resembled a windmill.
"Let's see if this works," she hesitated. "Theoretically, keeping the blades at an angle should generate horizontal thrust. But with one oar reduced, four blades might not be enough to propel the boat." "Of course, just tweak it slightly," Roland said, taking the quill from Anna and sketching the propeller's original form. "This design is better for underwater rotation than a windmill shape. You're spot on, but the contract requires a rudderboat. Let's stick with the first method—it's not about technique, but business strategy." He paused. "I need to measure the hull data now. Want to come along?" Anna blinked her azure eyes. "Sure!" After all, the best way to learn is to test theories in practice.
...
"Nightingale?" Anna couldn't help but ask as she followed the Prince to the doorway, where she saw the Nightingale still studying the blueprints on the table.
"Ah, you go ahead, I'll be right back." After carefully comparing the sketches in her hands, she concluded: Wasn't it just a matter of repositioning the wheels?