First, the land was turned over to loosen the soil. Then a small ditch was dug to channel the river water in, and the field immediately became a muddy expanse. But mud like this still couldn't be used to make brick blanks. It had to be trampled until it was properly kneaded.
In the past, those who had the means used oxen to trample mud, while those without oxen did it themselves. Luo Chong, however, had his own way of doing things—he used elephants.
Rou Rou and Hui Shan were still young, after all, and loved to play. Mud-trampling in particular seemed to have a natural attraction for creatures like elephants. They rolled and charged wildly through the mud, having the time of their lives and treating the work as a game. It was incredibly difficult to drag them out— they were even more stubbornly attached to the mud than wild boars were to the muck.
After much effort, they were finally lured out with Sweet Tree Root. The two brutes had turned into mud elephants, so Luo Chong took them to the river for a bath before driving them away to rest.
Once Rou Rou and Hui Shan's work was finished, the humans' work began. The kneaded mud was packed into molds, pressed solid, and turned into brick blanks one after another. After that, they only needed to be left out to dry.
They were only making brick blanks for now. Luo Chong wasn't planning to fire the bricks yet. That could wait until winter. Everyone would be idle then with nothing to do, and firing bricks in winter would make the kiln nice and warm. It was a blissful job—far more pleasant than firing bricks in summer.
The bricks were large. This batch was meant to encase the rammed-earth city walls, so there was no need to make them too small.
The work itself, however, progressed much more slowly. It wasn't because pressing the brick blanks took too long, but because most of the time was spent hauling mud and brick blanks around.
The bricks for the city walls were forty centimeters long, twenty centimeters wide, and twenty centimeters high—a standard rectangular cuboid. Yet they were extremely heavy. A block of wet mud that size weighed at least thirty or forty jin. Each person could carry one large load of mud at a time in a Woven Basket or on a Carrying Pole, then take it to the drying yard to be molded and dried.
The people were exhausted, while work efficiency remained low. Therefore, a convenient and speedy means of transportation had to be produced immediately.
When it came to transport, the first thing that naturally came to mind was a cart. It saved effort, and its carrying capacity increased several times over. The soul of a cart, of course, was its wheels.
Given their current conditions, Luo Chong had essentially no choice. Wooden wheels were the only path available. But how to make wooden wheels was a problem.
In his previous life, Luo Chong had changed car tires and repaired tank tracks, but as for wooden wheels, he had only ever seen them on television.
As far as he remembered, wooden-wheeled carts had practically vanished in China. Even the occasional horse-drawn carriage used Rubber Tires. Only the British Empire still preserved plenty of such antique contraptions, especially the Queen's carriage.
A wooden wheel's main structure should consist of three parts, roughly similar to a bicycle wheel, except without a tire. First was a round center fitted over the axle. Luo Chong didn't know what the ancient term for it was, so he decided to call it the Wheel Hub—plain and easy to understand. Many wooden rods for support would be inserted into the Wheel Hub. Bicycle wheels called them spokes, and Luo Chong would call them spokes too. Finally came the outer wooden ring, which was also the most difficult part of the wheel to make.
In language class, they had learned, "Straight wood, when aligned with the marking cord, can be bent and made into a wheel." Ancient wheels were made by bending straight wood and then baking it into shape. But no matter how ingenious the ancients were, they couldn't simply bake a straight piece of wood into a complete circle. Therefore, wheels were generally made in sections.
A small-diameter wheel needed at least two pieces of wood for its outer ring, or perhaps three. In any case, the more sections there were, the smaller the curve of each piece. That way, a circle could be broken down into multiple bow-shaped segments. A circle was hard to bend, but a bow shape was surely manageable—otherwise, how could a longbow be bent into an arc?
Luo Chong had never seen wooden wheels being baked, but he had seen oak wine barrels being baked. Wine barrels were generally made by bending and baking Oak Wood planks into shape. Luo Chong, however, was going to use Oak Wood to make wheels.
With the new project underway, finding apprentices naturally came first. Among the Han Tribe's carpenters, Mutong had the greatest talent. This fellow had come up with the idea of using glowing-hot charcoal to burn out a barrel in a round wooden post. He was clearly no ordinary mortal.
The other was Wooden Porpoise. Wooden Porpoise was honest, disliked interacting with others, and wasn't much of a fighter. He had no outstanding traits. Yet someone who kept silent like him, if he focused on one thing, was bound to achieve no small amount. So Luo Chong called him over as well. From then on, the two of them would be the Han Tribe's dedicated carpenters.
With helpers in place, Luo Chong still had to handle the main work himself. After all, asking someone else to calculate pi wasn't realistic. That was something he would have to teach them little by little later.
The Han Tribe's first cart was built according to practical needs: an ash cart primarily used to transport mud. It had a pair of wheels in front, two legs in the back, and two long handles. It was a two-wheeled handcart, just like the carts used to push cement around construction sites nowadays, except that it was made entirely of wood.
The wheels weren't large, measuring only seventy centimeters in diameter—nothing compared to the enormous ancient wheels that stood as tall as a person. The Wheel Hub was made directly from a section of roundwood. A red-hot copper rod was used to burn straight through the center, after which a Hand Drill was used to widen the hole and it was polished smooth.
Then the points where the spokes connected were evenly marked around the Wheel Hub's outer diameter. The holes were made with the same red-hot copper rod and Hand Drill, this time to increase production speed.
The outer rings of the wheels were made from two pieces of Oak Wood baked into shape—two rough semicircles. Baking Oak Wood naturally required care. The bark side had to face outward, because the wood near the bark was harder. Placing it on the outside made it wear-resistant, while the softer heartwood was suitable for being squeezed inward as it contracted.
First, the sawn oak strips were doused with water and placed around a prepared thick round log to set their shape. Then a loop of Thick Hemp Rope was wrapped around them, cinching the oak strips tightly against the log. Finally, a lit clay basin was placed underneath. As the strips were heated over the fire, the rope loop was twisted tighter with a wooden stick, gradually bending the oak strips into shape.
The three men spent an entire day making this little cart. Its wheels had only ten spokes, and even those had been planed out one by one with a Planing Knife. The speed was far too slow, so Luo Chong planned to improve the process next time.
The two oak sections forming each outer ring were secured at the joints with U-shaped copper nails. The axle was wooden too, and the cart was reasonably steady when pushed. Above it sat an ash box made from wooden boards, with all the joints using mortise-and-tenon construction. Aside from the four copper nails on the wheels, the entire cart was made of wood.
As soon as the first little cart was built, it was handed over to the Engineering Team for use. Luo Chong also began experimenting and observing where it could be improved.
After the first day's use, the tribespeople were deeply interested in this new means of transportation. Ever since Luo Chong had invented woven baskets, the Han Tribe had finally abandoned the era of carrying everything by hand and on their shoulders, switching to Back Baskets and Carrying Poles instead. Now that carts had appeared, this would be another revolution.
The tribespeople were overjoyed, but Luo Chong wasn't optimistic. The tools and methods were crude, and this little cart could only be described as shoddily made. In terms of performance, it could merely "move"—that was, it would turn when pushed—but it absolutely wouldn't last long before falling apart.
There were too few spokes. Ten spokes were nowhere near enough to support a circle. Ancient wheels had more than twenty or even more than thirty spokes. With too few spokes, the outer ring couldn't be supported in a circular shape. Once the load grew heavy, the outer ring risked splitting apart or deforming.
The Wheel Hub was also too narrow. Its contact length with the axle was too short, causing the wheel to wobble from side to side as it rolled. Next time, the Wheel Hub would have to be lengthened.
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