"Come, everybody, come over here. Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 info" Cao Cao led everyone to the edge of the pool, where there was a small wooden boat, "Chong'er, if this boat is coming towards you from a distance, which part of the boat do you see first?" ”

Cao Chong thought for a while, "I think it should be the bow and mast of the ship." ”

Cao Cao nodded and said, "That's true." If the water is flat, then we can see both the mast and the bow. However, Daddy saw the top of the mast first, then the sail, and finally the bow. This shows that the sea is not flat, at least it is an arc. ”

"It's a pity that the slave family has never seen the sea. Is there any other way to prove it? Cai Wenji still didn't believe it.

"Yes." Liu Yong smiled, "You can erect two wooden poles of the same height in two places hundreds of miles from east to west, and measure the length of the shadow of the wooden pole at the same time." If the earth is flat, then the length of the shadow is the same, and if the earth is round......"

"The shadow is not of the same length, and the shadow grows closer to the west." Cao Pi interjected.

"Eldest Prince, that's exactly the case. The farther apart the two places, the more obvious the results will be. ”

"After the four seas are settled, there will definitely be a test." Cao Cao also recognized Liu Yong's inference in his heart.

Cao Zhi said: "Mr. said that if you look at the mast of the ship returning from the sea, you can know that the ground is round, and we have never seen the sea, so we dare not speculate; Mr. also has the theory of standing wood measurement, but as Mr. said, in the humble opinion of the students, it can only prove that the earth is an arc, why must it be round? Many people here had this question, and when Cao Zhi asked it, they all looked at Liu Yong to see how he answered. Cao Cao stroked his beard and nodded frequently, looking at his beloved son's eyes with a look of approval and love.

"Third son, that's a good question." Liu Yong admired and praised in his heart. Cao Zhi felt proud for a while, but heard Liu Yong ask again: "Do several sons think the same way?" ”

Cao Chong stared at the big black eyes and replied, "Chong'er doesn't understand either, please make it clear to Mr." Cai Wenji and Cao Pi also echoed.

"Actually, there's a very simple way. We see it almost every day. Everyone was stunned, Liu Yong was not in a hurry, and pointed to the crescent moon hanging in the sky outside the hall. He smiled and said, "That's it." ”

Cao Chong was surprised: "Can the moon prove that our earth is round?" ”

Liu Yong smiled lightly and said, "Yes." He asked again: "Have you read Zhang Heng's "Lingxian"? Cao Cao's son has been familiar with poetry and books since he was a child, and he nodded yes. Only Cao Chong said in a soft voice, but he hadn't read it, which made everyone laugh. The atmosphere in the audience was much more lively.

Liu Yong hugged Cao Chong in his arms and asked softly, "Chong'er, do you know that the moon will shine on its own?" ”

Although Cao Chong is young but extremely smart, listening to Liu Yong's question, he knows that the answer will not be simple. After thinking for a while, he shook his head slightly, and said unwillingly: "Mr. must have said that the moon itself will not shine." It's just that Chong'er doesn't know why. ”

Liu Yong gently touched his hair and said lovingly: "Chong'er is a young grade, it doesn't matter if you don't know." Eldest Prince, can you tell Cangshu Gongzi why Zhang Heng thinks that the moon will not shine on its own. ”

"Because if the moon could shine on its own, it would always be a circle like the sun, and it would not take on the shape of a semicircle, a crescent, etc." Cao Pi replied confidently.

"That's what the eldest prince said." Liu Yong praised. Cao Cao looked at Cao Pi and couldn't help but smile. There was a smug feeling in my heart. I heard Liu Yong say again: "Then why does it look like the moon is shining on its own?" This is because the moon is like a copper mirror, although it cannot emit light on its own, it can reflect the light of the sun. ”

Everyone pointed their ears up, and Liu Yong explained: "When we look at the moon, sometimes it looks like a sickle, sometimes it looks like a disk, why is that? That's because our earth blocks out the sun's rays, and the part that is obscured is a shadow, so the moon waxes and wanes. Now if we look at the moon in the sky, isn't it an arc that covers the moon? Think again, everyone. Towards the end of the month, we see if there is a round black shadow, and the moon is only left with a bright edge. What is that dark shadow? It is the shape of the earth beneath our feet. ”

Everyone shouted in a low voice, such a simple and intuitive truth. I haven't paid attention to it for thousands of years. In fact, it is not to blame them, in most Chinese dynasties, only the so-called orthodox and classic classics represented by Confucianism are studied, and others such as astronomy, geography, and mathematics are regarded as sideways, and they rarely dabble in, let alone devote themselves to study.

"It's just that I still find it weird." Cao Zhi grinned.

"What's weird?" Cao Pi asked.

"You say that our land is really round. Doesn't the one who lives below live with his head down, and doesn't he fall? ”

Everyone couldn't help laughing when they heard this, Cai Wenji couldn't help it, she hurriedly turned her head, took out a silk scarf to cover her mouth, and secretly wiped away the tears that popped up in her eyes.

Liu Yong didn't laugh, just waited quietly. Cao Cao first stopped laughing and said, "Don't laugh, although Chongru's words are strange, what he said is very reasonable." I think there must be a reason in it that we don't know. Everyone hurriedly stopped laughing, and they all looked at Liu Yong and listened to how he explained.

Liu Yong was not in a hurry, picked up an orange from the table, and said to Cao Zhi: "Throw this orange into the air, where does the third prince think it will fall?" ”

"Of course it fell to the ground." Cao Zhi was puzzled.

"Have you ever thought about it, why don't the oranges fall to you or to me, and they don't fall from the sky, but only to the ground?" Cao Zhi was stunned for a moment, and everyone was puzzled, this phenomenon is extremely common, but who has ever thought about the deep meaning? Liu explained: "Whatever it is, it will only fall to the ground, and this is called gravity. The stones on the mountain will fall down the mountain, and the river will flow from the high to the low, all because of gravity. The center of our gravity is at the center of the earth. Liu Yong pointed to the orange, "So, whether you are above, on the side, or below this orange, it is actually the same." ”

"It seems to mean that, but I still don't understand it too much." Cai Wenji was still a little confused.

"This can only be experienced slowly. It was said below that the earth is round. But wherever you throw a stone, it will fall straight down. ”

Everyone thought for a while, but there was no sound around. After a moment, Cao Cao suddenly asked, "Where did Chongru learn about this?" As far as the old man knows, there will be no such clever saying in the Western Regions, right? ”

Cai Wenji nodded on the side, she was also puzzled in her heart, looking at Liu Yong to see how he answered.

Liu Yong already had a statement in his heart, arched his hand, and replied calmly: "Don't hide it from the prime minister, be greedy for fun in the next hour, and like adventures." Once, while climbing a mountain, I stumbled upon a cave that was extremely secretive. There are many murals and ancient books in it, which are actually written in the Central Plains script, and Liu Yong often goes to see them, and there are such answers in it. ”

"Oh." Cao Cao was extremely curious and asked eagerly, "Is there a technique of immortality or predicting the future?" ”

Liu Yong sighed in his heart, the more powerful people care about this, even Cao Cao is no exception, and hurriedly replied: "That's nothing." ”

Cao Cao's eyes darkened, Liu Yong couldn't bear it in his heart, and persuaded: "Prime Minister, life and death are fateful, and wealth is in the sky." According to Liu Yong's humble opinion, the so-called techniques of immortality and predicting the future are all deceitful. Think about how the first emperor is, even if he visits thousands of mountains at home and abroad, and exhausts the strength of the whole country, in the end, it is not a piece of loess. The prime minister is wise and wise, so why should he care about these illusory things? ”

"Good. Chongru is right. Cao Cao was free and easy, and he immediately put it behind him.

Cao Chong saw that Liu Yong easily answered the difficult questions that he couldn't figure out, and he admired it so much that he asked all the tricky and strange questions that no one usually could solve.

Liu Yong naturally likes children, and because he loves Cao Chong very much, he has to answer all questions. Cao Chong liked it even more, so he stuck to Liu Yong's side, and he couldn't hug it.

Cao Cao stroked his beard and laughed: "Chongru, how about seeing that you and Chong'er are extremely close to each other, so you often go to the mansion to be with your sons?" ”

Liu Yong returned to Liu Bei's mansion and reported to Liu Bei about taking Hanoi, governing Luoyang, and raising guards. Zhang Fei listened to the itchy technique, Guan Yu's face sank like water, Liu Bei pondered for a while and said: "Liu Bei is very grateful for such an act, but in this way, Cao Cao will be more suspicious of the relationship between you and me, and Liu Bei is only afraid that it will be more difficult to get ahead!" ”

Zhang Fei's eyes widened, "So what?" I see that Chongru is doing the right thing, what is the use of Cao Cao's bird official coming? ”

Guan Yu said: "You don't know, so it will be even more difficult for us to leave Xudu." ”

Liu Yong asked Liu Bei again: "Uncle Huang, what is the big deal in the court?" ”

Liu Bei shook his head and said, "There is no big deal in the imperial court. is something, where can idlers like Liu Bei know. ”

Liu Yong wondered in his heart, what about the "edict of clothes"? Why didn't Liu Bei tell me? Is it because you're worried that I'm going to leak the news? Although he felt a little unfair in his heart, Liu Yong had no choice but to comfort Liu Bei and said: "Cao Cao is afraid of the emperor's uncle's talent and virtue, and he dare not reuse it." Liu Yong thought that the emperor's uncle only needed to keep his head in obscurity, with the heart of Cao Cao, and wait for the opportunity, and there would be a day when he would come out. ”

Liu Bei nodded, "Chongru is extremely right. Liu Bei also has this plan, and now he is opening a garden in the backyard, watering and planting vegetables, and does not ask about political affairs. ”

The next day, Cao Cao sent an order to Liu Yong's prime minister's mansion to discuss matters. Liu Yong was helpless, Zhang Fei was indignant, Guan Yu was thoughtful, but Liu Bei was as calm as before, and comforted: "Liu Bei knows his heart of admiration, you can rest assured to go." ”

Liu Yong said goodbye to the three of them and went to the Prime Minister's Mansion. Following the people through the corridor on one side, there was a melodious sound of silk and bamboo in his ears, Liu Yong glanced at it, and saw more than a dozen young women in the courtyard of the partition wall, with long sleeves and dancing steps, and couldn't help but take a few more looks.

Suddenly, a woman turned her head and faced Liu Yong, who couldn't help but be surprised when she saw it. (To be continued.) )