Chapter 33

Cattle are generally not eaten as frequently as other meats, which include dog, chicken, duck, and fish. Lamb is the next most common. In the early Tang Dynasty, people did not have the habit of making lamb soup. They would slice cooked lamb, pour garlic paste over it, and sprinkle some salt before eating it. Alternatively, they would boil it in hot water, add some salt, and eat it. There were not many ways to prepare it, unlike later times when there were red-braised and stir-fried dishes. Roasted lamb was available, but with few seasonings, it only tasted salty and was not very appetizing. Lamb soup, on the other hand, is both delicious and good for the stomach. A large pot set up on the street would fill the entire street with its aroma. A bowl of lamb soup, with some thin pancakes cut into strips and soaked in the soup, would be a satisfying meal, leaving one feeling warm and content. The enduring popularity of lamb soup over a thousand years is a testament to its value.

In the village where Xia Hongsheng used to teach, there was a shop that sold lamb soup. He and the other teachers often went there to drink it, and it was very tasty. Because he was a teacher to their children, the owner shared the secret, which was simple: a piece of pine wood and some white芷 (angelica root). However, there were some nuances. The pine wood had to be peeled and aged for a while; otherwise, the pine resin would affect the taste of the soup. The pine wood was mainly used to remove the muttony smell and absorb the impurities that cooked out of the meat. The white芷 (angelica root) was the key to enhancing the flavor, though the pine wood also played a role, albeit a lesser one.

With these two ingredients, the lamb soup would be fragrant, not muttony, and rich and clear. Combined with Sichuan pepper, the taste was excellent.

Xia Hongsheng promised to only make the soup at home and not share the recipe, and it eventually became his secret.

The lamb bones were simmering in an iron pot. Xia Hongsheng set up another pot, added water, and then brought out two large buckets. He poured all the salt-impregnated soil he had bought into the buckets, added water, and found two sticks to stir the mixture, accelerating the dissolution of the salt in the water.

These two large buckets of salt solution should yield a small bag of good salt. As Xia Hongsheng stirred the buckets, he sniffed the lamb bone soup simmering in the iron pot. The aroma was already starting to waft out, and his appetite was growing. When the soup was done, he would fish out the bones, add some seasonings, and enjoy a satisfying meal. Unfortunately, chili peppers had not yet been introduced to China. Although Sichuan pepper was spicy, it lacked the depth of flavor that chili peppers provided. Not only chili peppers, but many other foods from later times were not yet available, such as corn, sweet potatoes, and potatoes. Many of China's foods were introduced during the Ming Dynasty, when Zheng He's voyages brought back many new species. At the same time, European countries were beginning to expand overseas, ushering in the Age of Exploration. Many species were brought back to Europe by ships and then entered China through the Silk Road and the Maritime Silk Road.

A few days ago, he had heard some elderly neighbors chatting about how the weather was not favorable this year, and there might be a famine next year. The mention of a famine frightened everyone, and their faces changed. In the early Tang Dynasty, there were few types of grain, and yields were low due to technological limitations. The ongoing wars had also left many fields fallow. If a famine were to occur, it could lead to a terrifying situation where people would resort to cannibalism. If there were as many vegetables and grains as in later times, such a tragedy might be avoided. Unfortunately, Xia Hongsheng was just an ordinary person, unable to build large ships or advance the Age of Exploration to bring back those food crops from the Americas. So he could only sigh and sniff the air, noting that the lamb was starting to cook well.

"Hey! What delicious dish is Jing Shi making? It smells so inviting!" A voice exclaimed from behind. Xia Hongsheng turned around and saw Yan Shigu, the middle-aged scholar, and a smiling Xu Qixian, along with someone he didn't recognize, standing outside his courtyard.

Seeing Xu Qixian's expression, Xia Hongsheng guessed who the unfamiliar person was. "Hey, they're coming to my door?!"

Xia Hongsheng smiled, threw the sticks back into the buckets, and quickly walked out to greet them. "Student greets Master Yan and Brother Xu. I greet this senior and Uncle Xu."

After the formal greetings, the group smiled. In ancient times, proper etiquette was highly valued. Good manners left a good impression, while poor manners were seen as disrespectful, and even talented people could be overlooked. This was why many talented but eccentric scholars often went unrecognized. Years of experience had taught Xia Hongsheng that to get along smoothly, one needed to show respect and obedience to the system and authority, even if it was just for show. It was better to keep any complaints to oneself.

"Hmm, not bad, indeed a well-mannered young man," Xu Qixian's uncle stroked his beard and nodded.

"Uncle Xu, you flatter me. It's all thanks to the teachings at the academy. I am not worthy of such praise," Xia Hongsheng replied politely, then turned to Yan Shigu and asked, "Master Yan, what brings you here today? I will do my best to assist."

Yan Shigu smiled and shook his head. "Today, it is Xu Daren who has something to discuss with you. I and Yan Zu are just here for the fun of it."

"Oh, you two, one of you will be a great literary figure in a few years, and the other is likely an official from Chang'an. You came to my humble abode for fun?" Xia Hongsheng thought to himself but kept a straight face. He then turned to Xu Qixian's uncle and asked, "Uncle Xu, what can I do for you?"

Xu Qixian's uncle first turned to Yan Shigu and bowed respectfully. "Lord Yan, how can I, a lowly official, be called 'Lord'? You embarrass me!" He then turned back and took out some papers from his wide sleeve. "There is no other reason. Yesterday, I examined my nephew and was surprised by his significant improvement in mathematics. When I asked him, he admitted that you taught him. I was very impressed. Even the students in the National University's mathematics department do not have such a high level of skill! So, I wanted to meet you."

"Uncle Xu, you flatter me. Brother Xu and I are like brothers. If you want to see me, you could just send a message through Brother Xu, and I would come to visit," Xia Hongsheng replied respectfully, making Xu Qixian's uncle nod in satisfaction.

"May I ask, where did Jing Shi learn these mathematical principles that you taught to my nephew? Such a great mathematician..." Xu Qixian's uncle was visibly excited, showing his passion for the subject. However, Xia Hongsheng inwardly sighed. In his previous life, he had been severely biased in his studies, and mathematics was his weakest subject. It was already a struggle to remember what he did.

Hearing this, Xia Hongsheng scratched his head. Should he say it was taught by a mountain sage? Just as he was hesitating, Yan Shigu spoke up, "Xiao De, wait a moment. These symbols on the paper are quite novel. I heard about them from Qixian at the academy, but he didn't explain them well. We should ask the person who knows best."

Xu Xiaode bowed and stepped back, no longer asking. He handed the paper to Xia Hongsheng, who saw that it contained Arabic numerals.

He respectfully invited the four guests to sit down, poured tea for them, and then went to get a quill pen and ink. He then sat down and explained, "These are a method of notation I learned from a sage I met on Laojun Mountain. It is simple, easy to write, and convenient for calculations. For example, if I bought thirty-seven pounds of salt-impregnated soil, the traditional method would record it as 'THIRTY-SEVEN POUNDS,' but with these numbers, it can be written as '37 POUNDS.' This method is not only easier but also saves space. The advantage becomes more apparent when dealing with large numbers."

"These symbols... hmm, very good! They have great potential!" Yan Shigu stroked his beard, his eyes shining. He then turned to Xu Xiaode and said, "Xiao De, since Jing Shi taught these to your nephew, you should study them thoroughly and write a report. If this method can be widely adopted, it will greatly benefit our dynasty!"

Xu Xiaode was taken aback, his eyes wide as he looked at Yan Shigu. He quickly stood up and bowed. "Lord Yan, this..."

"No need to worry. This is something Jing Shi taught to Qixian, and it can be considered a discovery of your family. No need to mention it further," Yan Shigu waved his hand, cutting off Xu Xiaode's words.

Yan Shigu looked at Xia Hongsheng, who was still smiling and unconcerned, and nodded. He then asked, "Jing Shi, why did you buy so much salt-impregnated soil? Is it related to the aroma in your courtyard?"

"Not exactly. The aroma is from the lamb soup I'm making. Today, I have the pleasure of serving Master Yan, this senior, Uncle Xu, and Brother Xu with a fresh taste!" Xia Hongsheng smiled. "As for the salt-impregnated soil, I will not hide it from you, Master Yan. This soil cannot be used directly as salt because it contains many impurities, some of which are toxic. I have been experimenting with a method to extract good salt from it. I succeeded yesterday, and today I bought more to try again."

As he spoke, the four guests were stunned. Even Yan Shigu's hand trembled, pulling out a few beard hairs without noticing. Xu Qixian's uncle stood up abruptly, his arm trembling as he pointed at Xia Hongsheng. "You, you can extract good salt from salt-impregnated soil?!"