Imperial Master of the Ming Dynasty

"Time flies so fast. After this class, Mr. Jiang will be released from prison in two classes. I don't know what this class is about?"

In the secret room, Zhu Di looked at the familiar chair and felt a little emotional for a moment.

Looking back on these short few months, it feels like a world away. I don’t know how many decisions, thinking, and theories that changed Ming Dynasty came from this wall.

After listening to this lesson, Zhu Di planned to go to jail himself to see Jiang Xinghuo again.

After all, it has been too long since the last time he played "Colonel Yan".

"Your Majesty, I heard the report from the Sanbao eunuch is about the study of astronomy." Ji Gang replied respectfully from the side.

"oh?"

Zhu Di's eyes flashed with subtle surprise: "Mr. Jiang still knows astronomy?"

"The banished immortal probably knows everything, right?" Zhu Gaochi echoed with a smile.

Zhu Di nodded and said nothing more.

Today, it was just the father and son, Ji Gang and the two minor officials. The other ministers were squeezed so hard that they really couldn't spare any time.

"What we said today."

However, at this time, the sound-amplifying ceramics on the wall were eavesdropped, and intermittent fuzzy sounds were heard, even a bit harsh.

"what happened?"

Zhu Di asked with some displeasure.

Ji Gang immediately walked to the loudspeaker ceramics in front and pretended to inspect it for a moment.

You wouldn’t know it until you checked it, but you were shocked when you checked it and found that some of the loudspeaker ceramics had cracks like spider webs for some reason.

Ji Gang gritted his teeth and said, "Your Majesty, it seems that there is something wrong because it has been in disrepair for a long time."

After all, this is the "walls have ears" method passed down from the Hongwu Dynasty, but since the 20th year of Hongwu, Zhu Yuanzhang ordered the Jinyiwei torture tools and instruments to be burned, and the prisoners were transferred to the Ministry of Punishment for trial. At the same time, he ordered all internal and external prisons to be tried by the Sanfa Division, and Jinyiwei was abolished.

So far, it has been fifteen years.

Although the eavesdropping and amplification wall in the prison has not been exposed to wind and sun for fifteen years in the secret room, its natural aging is enough to weaken its performance.

Once before, when we were talking about "Kamikaze" and "Subtropical Low Pressure", a huge and harsh noise appeared on the sound amplifier wall, which was actually a warning of some kind.

"Something went wrong?"

Zhu Di frowned slightly, and then ordered: "Find someone to repair it quickly."

"According to the order!"

Ji Gang immediately agreed, turned around and walked towards the door.

But where can I find someone to fix it?

You must know that what was burned fifteen years ago was not only Jinyiwei's torture instruments and instruments, but also a group of craftsmen who hid related secrets.

The craftsmen who built and maintained the loudspeaker wall had been exterminated long ago. Is it possible that Ji Gang dug one out of his grave?

Not long after, Ji Gang led two Jinyi guards to the loudspeaker wall, and tinkered with some strange tools for a while, even blocking the sight of Zhu Di and Zhu Gaochi with his body.

After doing this, Ji Gang turned back again.

At this time, Zhu Di and Zhu Gaochi both stood up and moved a little closer to the eavesdropping loudspeaker wall.

Zhu Di held his breath and listened carefully, but he still couldn't hear clearly. It was even worse than before. He could only hear a vague "buzzing" sound.

"Um?"

Zhu Di frowned slightly.

Although Zhu Di didn't understand the principle behind this, it didn't stop him from knowing that the current situation must have been repaired somewhere wrong, otherwise it wouldn't be the current situation at all.

Ji Gang's heart gradually sank.

Oops, all the tinkering went wrong.

"what happened?"

Sweat dripped from Ji Gang's forehead. He didn't dare to say anything, then turned around and started repairing like a blind cat but a rat.

Seeing that he couldn't fix it even after a while, Zhu Di simply sat back in his chair and continued to listen patiently.

"Squeak, squeak, squeak!"

It was repaired through the efforts of Ji Gang and others.

A moment later, the sound came from the ceramic loudspeaker again.

"Can any of you tell me what that 'squeaking' sound means?"

Zhu Di looked at Ji Gang and the two Jinyi guards beside him, narrowed his eyes slightly, and asked in a low tone.

"I am incompetent! I am guilty!"

Ji Gang knelt down with a pop and kowtowed repeatedly.

The two Jinyi guards next to them were also frightened and knelt down, not daring to say a word.

"snort!"

Zhu Di's face was as gloomy as water, and he suddenly snorted coldly.

Ji Gang immediately cooperated and acted in a timely manner, showing that he was shaking with fear, and even almost fell over due to the excessive force in the performance.

"Get off!"

Zhu Di waved his sleeves and said: "It's not good to do things like this. If it happens again, I will punish you severely!"

Ji Gang breathed a sigh of relief, quickly thanked him, and then retreated with two royal guards as if they were running for their lives.

Zhu Di's eyes fell on Ji Gang's back, with amusement in his eyes.

"This kid, he pretends to look like him, huh."

"Father has never been angry?" Zhu Gaochi also asked at this time.

I don’t know if Zhu Gaochi really couldn’t tell, or if he was deliberately cooperating with his father.

Zhu Di smiled and said: "Why are you angry? Tianwen and I don't understand it anyway."

Zhu Gaochi also smiled.

Zhu Di said to the good boy: "Since I can't attend this class today, I don't plan to attend it. I will go to the prison in a few days to see Jiang Xinghuo in person. If you want to stay here, I won't stop you."

Zhu Gaochi said that he planned to stay for a while, and Zhu Di left without saying anything.

"Tianwen, tsk tsk, I won't stay here and act like a fool."

Zhu Di thought in his mind, then curled his lips and left the secret room.

In the secret room, only Zhu Gaochi and two minor officials were left.

What Zhu Di didn't know, if he insisted on listening, he would definitely not make the decision to go to prison himself.

Because Zhu Di couldn't help but push the wall after listening to this lesson halfway.

Good boy, the unity of heaven and man has shaken you to your core!

How do you ask me, the emperor, to explain myself?

——————

Under the new crooked neck tree.

The obvious fact is that the number of students attending the lectures is getting bigger and bigger.

Two big men and one old man sat in front of Jiang Xinghuo.

Jiang Xinghuo, on the other hand, leaned against the tree trunk and showed no sign of respecting his elders.

Zhuo Jing was not surprised at all by Zhu Gaoxu's appearance. Obviously, Dao Yan had already informed Zhuo Jing before.

Zhuo Jing twisted his beard and said: "My little friend said that night that the calendar should actually be made with the sun as a reference to be most accurate. And this means that the sun should actually be our center, not that we are the sun. center of?"

Jiang Xinghuo nodded tiredly. He didn't sleep well today.

Zheng He interjected and asked: "If that's the case, how did we achieve correct predictions based on errors when we used to observe the movement of the sun and then calculate and formulate calendars?"

"Good question."

Jiang Xinghuo blinked his dry eyes, cheered up and said, "This is because the mathematics involved in astronomy is divided into two basic categories, one is called geometry and the other is called algebra."

"Ancient Chinese astronomy is longer than algebra but shorter than geometry."

"In other words, it's no problem for us to extrapolate based on long-term accumulated data, but it's very difficult to draw a model of solar motion."

Jiang Xinghuo casually drew a ○ pattern on the ground, and then drew a · pattern in the center of it.

"First of all, let me explain that this sun-earth trajectory is definitely wrong, but you can see how this simple geometric figure can be used to explain the movement of the sun when converted into the algebra most commonly used in ancient Chinese astronomy."

Jiang Xinghuo casually drew a few connecting lines at different locations, and then said.

"Actually, have you seen it? No matter how the sun moves, as long as these lines are connected together, since a year will always pass, as long as enough data is accumulated, each day will be in a different year. Under the situation, the observed conditions of the sun and moon will always produce similar results. As long as there are enough parameters, that is to say, the problem of geometric figures can be transformed into algebraic models to find approximate solutions, and the parameters The more, the more accurate this approximate solution is.”

Seeing that several people were in different states of understanding, Jiang Xinghuo further explained.

"In other words, for example, the "Time Calendar" used by the Ming Dynasty is equivalent to segmenting the movement of the sun every month, every day, and even every hour and every moment, and then using cubic equations to do the square root. to find an approximate solution.”

Terms such as equations and square root are all found in ancient Chinese mathematics, so there is no obstacle to the students.

And as Jiang Xinghuo dismantled it, several people gradually understood.

To put it bluntly, as long as the observation base accumulated by China over thousands of years is here, the changes of the sun at every hour and every moment of every day have actually been repeated thousands of times.

In other words, each equation has been tested thousands of times.

Even pure empiricism has already obtained a fairly accurate approximate solution.

As a result, the solar motion model, which was originally a geometric problem, was dismantled into an algebraic problem using a method similar to "infinite severing a circle".

Therefore, the question "How can we make correct predictions based on errors by observing the movement of the sun with the earth as the center, and then calculating and formulating the calendar?" has been answered.

Zhu Gaoxu also asked a question: "Mr. Jiang, what is the difference between these two observation methods?"

Jiang Xinghuo pointed to the person on the ground and said: "If we use this person as the earth or the sun to observe the other party, then what do you think is the difference between the traditional view of the earth as the center and the sun as the center?"

Zhu Gaoxu didn't understand, but that didn't stop him from giving the most intuitive answer.

"I don't feel any difference."

"Yes~"

Jiang Xinghuo smiled: "That is to say, from a certain point of view, neither the heliocentric theory nor the geocentric theory is absolutely accurate truth, because how can you know that the earth or the sun is the center of the universe?"

Zhuo Jing and Zheng He were stunned by these words.

Even if the earth is not the center of the universe, neither is the sun that shines and heats? So are we in the garbage dump of the universe?