It wasn't until Wang Dejin heard that a certain Hui merchant had donated a set of arithmetic books and was hired as a professor by Yenching University, and the ancestors of the Hui merchants who edited this set of books were also rewarded.

This naturally made Wang Dejin very moved, although he envied the reward that this Hui merchant received, but what made his eyes even more hot was the emperor's recognition of the ancestors of this Hui merchant in arithmetic.

Wang Dejin has been immersed in this set of books written by his great-grandfather for many years, and he thinks that his great-grandfather's knowledge of arithmetic is not weaker than anyone else's, but the only regret is that his great-grandfather has never been recognized by others.

Wang Dejin stroked the books that were already a little damaged in the corners, and finally made up his mind to try to donate the books to the court again, so that the great grandfather's life's work would not be buried.

In the afternoon of the same day, when Chongzhen came to the Huitong Hall again, he happened to see a merchant representative kneeling on the side of the road with a box of books.

Zhu Youzhen said to the officials of the same hall who came to greet him: "Who is this person?" What does he want to do? ”

"Back to Your Majesty, this is Wang Dejin, the representative of the Jin merchants, who said that he has books that he wants to dedicate to His Majesty, so he is waiting here."

After listening to the explanation of the officials of the guild hall, Zhu Youzhen looked at Wang Dejin, who was kneeling beside him, and said indifferently: "Then arrange a room, and then bring him to meet me, and postpone the meeting of the representatives of merchants from Yunnan and Guangxi." ”

The officials of the Huitong Pavilion hurriedly walked to the front and led the way for the emperor. In a well-lit room, Wang Dejin was brought in.

Wang Chengen took the book from Wang Dejin and put it in front of Zhu Youzhen, and then silently stood behind Chongzhen.

Zhu Youzhen glanced at the book he pulled out, and found that it was not a printed book, but a handwritten book, which made him feel a little contemptuous.

Although the handwriting is round and neat, Chongzhen doesn't think that books that can't even be printed will bring him any surprises.

However, seeing that the content of this book is about mathematics, not some kind of fairy and weird, in order to shape the social atmosphere that respects mathematics, he still decided to deal with this representative of the book a little.

Zhu Youzhen casually flipped through the books, chatting with Wang Dejin and talking about the content of the books.

Wang Chengen listened to the conversation between the emperor and Wang Dejin on the side, only to feel that his mind was in chaos, and he didn't understand what the two were talking about at all.

However, the emperor's contemptuous attitude at the beginning gradually became serious. After talking for a while, the emperor seemed to feel that he could not express it clearly with his mouth, so he ordered the subordinates of the same hall to bring blackboards and chalk.

The representative of the merchants, who had been kneeling far away in the hall, was called to the emperor's side and asked him to express some of the contents of the book on the blackboard.

Seeing the change in Chongzhen's attitude towards this merchant representative, Wang Chengen, who was originally disdainful of this merchant representative who wanted to win the emperor's favor with his book, also smiled at Wang De's progress.

The conversation between Chongzhen and Wang Dejin continued into dusk, and the original meeting with the representatives of the two provinces had obviously been forgotten by the emperor.

Although the officials of the household department tried to come and urge Chongzhen to meet with the merchant representatives several times, they were all blocked by Wang Chengen.

Since ascending the throne, it was the first time that Wang Chengen had seen the emperor talk about one thing with such a cheerful and engaged fan.

As the eunuch with the closest relationship with the emperor, Wang Chengen always hoped to help the emperor find a way to relax his spirit.

An emperor who has no preferences and has always been nervous is by no means good news for them, the close servants who serve the emperor in the palace.

These great eunuchs in the palace knew very well that although there was a cabinet to help the emperor deal with government affairs, the government affairs after being screened by the cabinet were still quite heavy tasks.

The emperor in history who can easily navigate this pile of official documents is only Emperor Taizu Gao. However, Emperor Taizu Gao was reckless and knew the world well, so he was not tired of reviewing these official documents.

But Taizu, who has no hobbies, can't be explained simply by being strict with the eunuchs around him.

Therefore, the eunuchs around every emperor hope to find the emperor's preferences, so as to relax the emperor's nerves in the tense state affairs, so as not to bring their anger back to the harem and vent it on them.

Second, even if you make a mistake, you can turn big things into small things and small things into nothing by voting for the emperor's favor.

Then after Chongzhen ascended the throne, he seemed to be very interested in everything, but he had no special preferences for anything, which made these eunuchs in the palace a little confused.

Today, since Wang Chengen has seen the seriousness shown by the emperor, he will naturally not let go of this opportunity to understand the emperor's hobbies. The only regret is that although he listened to it for an afternoon, he still didn't understand anything.

When the handwriting on the blackboard began to blur, Zhu Youzhen realized that the sun had set in the west, and before he knew it, he had been talking with the businessman in front of him for an afternoon.

The Tian Yuan technique and the method of multiplication and multiplication recorded in the "Treasure Book of Ancient and Modern Arithmetic of the New Collection of Tokens" are one step ahead of the previous algebraist Yang Hui, and the concept of derivatives is preliminarily deduced in the book.

This was an eye-opener for Chongzhen, who once thought that if he wanted to promote the study of calculus, he must rely on Western mathematics as the foundation.

Whether it is to calculate the quadratic parabola of the trajectory of a shell, or to study the tangent of the curve of the optical principle of the grinding lens, the calculation of calculus is required.

The advent of calculus will transform astronomy, mechanics, optics, heat and other disciplines into mathematical problems, and then promote the development of natural sciences by solving these mathematical problems.

To put it simply, the emergence of calculus is to allow people to use mathematics to analyze the whole world, rather than just using their eyes to understand the world.

However, it is a pity that although he learned calculus in college, Su Changqing had already returned it to his teacher. The only thing he could remember was a few symbols and the simplest calculus.

In this afternoon's discussion, Zhu Youzhen recovered some of his memory of calculus. For Wang Dejin, it is the door to a new world. But if he wanted to officially step into this new world and start the theory of calculus, he obviously lacked something.

Zhu Youzhen put down the chalk in his hand, turned to Wang Dejin and said enthusiastically: "This book of "Treasure of Arithmetic" will be published at my expense, and it will also become a textbook for various schools.

For Mr. Wang, who compiled this book, I will posthumously seal it and record it in the Who's Who of Scientists of the Academy of Sciences.

As for you, I would like to hire you as a professor of mathematics at Yenching University and enter the School of Mathematics to study mathematics, are you willing to accept it? ”

Wang Dejin was still unwilling, he hurriedly knelt down to Chongzhen to thank him, and accepted the emperor's reward for him.

When Chongzhen and Wang Dejin were eagerly discussing mathematical problems, a long snake-like convoy outside Jinzhou City was coming along the road on the wasteland towards Jinzhou City.

A convoy of nearly twenty carts, escorted by a small group of Ming cavalry, meandered forward, each covered tightly with leather.

A group of Ming army scouts who routinely went to patrol the border of Sanchahe Fort suddenly stopped after seeing this team of chariots and horses on the road.

Zhao Baishun, the leader of the general flag, looked at this strange convoy and muttered a little in his heart. An old soldier behind him interjected indignantly: "Mother, we fought to the death with these Jiannu in Biansai, but these officials and masters have never cut off their benefits, and now they are all doing business with Jiannu openly." ”

The old soldier's complaint immediately resonated with most of the cavalry in this small group. Zhao Baishun's back was a little cold, and he could feel the dissatisfaction of the soldiers behind him.

After the slave chief Nurhachi raised an army against the Ming, the Ming army was defeated repeatedly, and I don't know how many sergeants' lives were lost in this black land of Liaodong.

For these low-level sergeants, they couldn't understand why the Liaodong Ming Army was fighting like it was now.

Only more than ten years ago, the Ming army was a famous existence in this land, although the Ming army was not victorious in the battle with foreign enemies, but never encountered the end of successive defeats against the same enemy, and every time it was a crushing defeat.

Every time they lost a battle, they could always hear the news that there was a Jiannu internal response within themselves. And those high-ranking officials who enjoy the preferential treatment of the imperial court are often the first to betray the imperial court.

This greatly damaged the morale of the low-level soldiers in Liaodong, and they gradually began to think that the Liaodong army was full of internal responses to Jiannu, especially the generals in the army.

After losing the battle with Houjin, the soldiers at the bottom died, and their families had to deduct even their pitiful pensions. And those generals, regardless of victory or defeat, can enjoy glory and wealth in the court and Jiannu.

In this situation, every time they fought against Houjin, these soldiers no longer focused on combat, but thought that they could not be betrayed by these generals and turned into unexplained battlefield artillery.

Although they were unwilling to be captured by Jiannu and become slaves of Jiannu. But as long as they fled back to the rear, the court did not dare to do anything to their defeated soldiers, and they still ate food and became soldiers.

As a result, every time they went to the battlefield, most of the Ming soldiers were not thinking about fighting against Jiannu, but about officers and soldiers being wary of each other and not being abandoned on the battlefield by the other party.

In this situation, the generals of the Liaodong Army finally invented the tactics of defending the city. In the field, you can run around in the wasteland. But being besieged in the city by Jiannu, everyone broke off the idea of escaping.

Thinking of this, Zhao Baishun sighed slightly in his heart, feeling that this Liaodong Army would be finished sooner or later. He pretended not to hear the complaints of the soldiers behind him, and commanded the old soldier who was the first to complain: "Wanhe, you go down and interrogate those cavalrymen who are in that fortress, why they appear here with the convoy." ”

The old soldier, who was called Wanhe, muttered a few words, and then rode his mount down the hill with a big grin.

Zhao Baishun shouted at his subordinates behind him: "cheer up Lao Tzu, Jiannu likes to use tricks the most, if there is something wrong on all sides, everyone will withdraw to the city." ”