The content of Meng De and Wang Yan's conversation was written into a letter by Wang Yan and handed it to Zhao Huan.

He closed the letter and could only sigh.

I left enough retreat for the generals and soldiers of the Song Dynasty, but unfortunately, the generals and soldiers of the Song Dynasty never paid attention to the retreat he left for them.

Wang Bing was like this at the beginning, but now it is like Wang Yan.

"The official family, tomorrow is the Lantern Festival, and Liu Yi has returned to the capital." Zhao Ying saw that the official family was not in high spirits and smiled and told the official family good news.

"Oh?" Zhao Huan became interested.

Liu Yi said he wanted to measure the vastness of the earth, but no one believed it, but Zhao Huan believed what he said.

When Zhao Huan met Liu Yi, Liu Yi held an instrument in his hand to meet him.

"The official family is in peace. Liu Yi has met the official family." Liu Yi said as he looked at the heroic Zhao Huan and said.

Zhao Huan signaled Zhao Ying to bring a stool for Liu Yi and said, "Please get up quickly. What is this?"

"This is the armillary sphere on the water transport meter platform. Li Chunfengming of the former Tang Dynasty, this is what it is to remove it. Do the officials still remember it?" Liu Yi looked at the officials and said with a smile.

Zhao Huan nodded. Of course he remembered this armillary sphere, the Water Transportation Eye Station is now telling the time to the people of Bianjing.

Of course he remembers this thing.

"The official family is the armillary sphere's armillary needle. The armillary sphere can move with the sun from time to time. The armillary sphere can point to the sun at any time. Then at night, the armillary sphere will still rotate, and the armillary needle will point to the ground." Liu Yi said with a smile and pointed at the armillary sphere.

Zhao Huan nodded. The mud needle could point to the sun, but at night, the mud needle pointed to the ground.

He knew why this was the case. He also talked about this to Li Gang at that time, saying that the sun was underground.

Li Gang also said that the sun is bright and brilliant, how can you be silent under the nine valleys?

Now it seems that Li Gang probably handed over this matter to Liu Yi.

Liu Yi smiled and said, "Officials, this time I went there, I have completed the Huntian Sayings."

"I wonder if the officials have heard of this saying: the shadow of the sun is one inch, and the ground is thousands of miles apart? That is to say, at the same time, the shadows of poles of the same height are one inch apart, and the ground is thousands of miles apart?"

Zhao Huan thought about it for a long time, but he had never heard of this statement.

Historical events remind: The sun shadow is one inch, a distance of thousands of miles. It is two places on the same meridian line. At noon on the summer solstice, the measured sun shadow length is one inch different, which means that the two places are one thousand miles apart.

Zhao Huan nodded, the system reminded him, and he smiled and signaled Liu Yi to continue talking.

"The monks from the former Tang Dynasty had been busy for many years, using zodiac spheres and water transport amphibian spheres in about thirteen places in the Tang Dynasty. After measuring one inch of the shadow of the sun, the distance between north and south was 351 miles and 80 steps."

"I am going out this time to calculate this. The sun shadow is one inch, and it should be 311 miles and thirty-two steps."

"Forget other things."

Liu Yi took out the letter from his sleeve and handed it out.

Zhao Huan opened it and looked at it. It was not a lot of formulas or a lot of calculation processes, but just a simple summary.

But it was this summary that gradually made Zhao Huan's breathing worse.

The steps from the east pole to the west pole are 233,500 miles and 75 steps. The vertical step is also 233,500 miles and 75 steps. The vertical step is also 233,500 miles and 75 steps.

Within the four seas, there are eight thousand miles east and west, six thousand miles north and south, eight thousand miles out of the water, and eight thousand miles received by the water.

Zhao Huan was a loss for not being a ignorant person. He still knew that the ancient Yi did not refer to the later Yi, but the ancient Yi did refer to the hundred thousand.

The meaning of truly expressing 100 million should be ten thousand.

Zhao Huan counted on his fingers for a long time. The content in Liu Yi's letter was about the length of the road that was about 46ooo kilometers.

History…Mathematical data reminder: The length of the equator is 4oo76 kilometers.

Within the four seas, it is actually about the territory of the Song Dynasty, which is about 5,600 miles east, west, south, and north.

Zhao Huan finally understood what Liu Yi’s letter was counted on!

But Zhao Huan looked at the sentence and made the vertical step of Hai reach the north and the north, 233,500 miles and 75 steps.

Zhao Huan fell into confusion. What does this mean?

The system did not jump out of translation, it seemed that it had entered the knowledge blind spot of the system again. This system is indeed a waste as usual!

Liu Yi looked at the confused expression of the official family and asked, "The official family means that the earth under our feet is actually a ball of 233,500 miles and 75 steps..."

Zhao Huan nodded. After Liu Yi's Sanskrit, he finally understood everything on Liu Yi's letter. What he wanted to express was that the earth was a ball.

Zhao Huan looked at Zazi with confusion. Although there was a big gap in data, at least he calculated that the earth was a ball.

Just how did it be calculated?

Liu Yi also knew that his words were a little bolder. The earth was the earth, how could it be a ball?

Liu Yi looked at the officials' confusion expression, and he knew his business, and he was afraid he would have done it.

He is a mathematician and is a top-notch mathematician, but he is not familiar with the court's report.

Liu Yi said a little helplessly: "Officials, I am not talking nonsense. My statement is well-founded."

"In the "Zhang Heng Armillary Sphere Notes" of the former Han Dynasty, the sky is like a chicken. The celestial body is round like a projectile, and the earth is like a yellow in the chicken. It lives alone in the sky, and the sky is big and the earth is small. There is water inside the sky, and the sky covers the earth, just like the shell wraps the yellow. The heaven and the earth stand with the energy."

"The Astronomy Records of the Former Tang Dynasty also mentioned this view, saying that it is mostly 526 miles and 227 steps, and it also mentioned this view in a note left by Su Song. The minister is not alone, so please let the official understand it."

Zhao Huan looked at Liu Yi and said a lot before he roughly understood what Liu Yi wanted to say.

In fact, Zhao Huan probably understood what Liu Yi said.

This involves a dispute between ancient heaven, the Gai Tian theory and the Hun Tian theory.

Gai Tian said that it is probably that the sky is round like a cover, the place is like a chess game, the sky is like a cover on the ground, and the earth is placed on the ground like a chessboard.

Huntian said that the sky is an egg, the stars in the sky are distributed on the egg shell, and the earth is the egg yolk.

Zhao Huan then realized that Liu Yi misunderstood his doubts. He actually wanted to ask how Liu Yi got this length, not to question whether the earth was a ball.

As a result, what Liu Yi explained to him was the argument between Huntian Theory and Gaitian Theory.

As for the knowledge system accepted by Zhao Huan, Huntian Theory is actually closer to the truth.

"I believe what everyone Liu said, the earth is just a ball." Zhao Huan replied with a smile.

Liu Yi was about to continue quoting the classics to prove that the earth is a ball, but when he heard Zhao Huan say this, he was stunned and said, "Officials, do you really believe that the earth is a ball?"

Zhao Huan nodded and said, "Liu, tell me how you calculated it."

Liu Yifeng said: "I was surprised when I thought the earth was a ball. Then on the summer solstice, I measured two places with the same shadow, namely Bianjing and Chang'an, with a difference of about seven and one fifth of the degree, about one fifty tenth of a week."

"But the shadow leader in Qiongzhou and the shadow leader in Bianjing is three inches different, and it is easy to get, 233,500 miles and 75 steps."

Zhao Huan nodded constantly, it was so easy to get!

He couldn't help but think of the three magic weapons of the mathematics teacher in his advanced mathematics class, which are easy to obtain, and the same is true for proof.

Zhao Huan looked at Liu Yi's expression and knew that he had accepted that the earth was a ball, which was too fast.

After all, in the later generations of the information technology era, there are still a lot of people who believe Diping!

"I believe that the earth is a ball because the moon is also a ball."

"Last year, the Work Relief Supervision made a model of goods, and the enlarged version of the bed crossbow, but it still hasn't been released. But he polished the water essence and made a thousand-mile mirror."

"I also burned glass in the Military Equipment Courtyard for half a year last year. Today is the Spring Festival. The large-scale Thousand Mileage Mileage Mileage Miles has been prepared. Let's go and have a look."

"The official promised Concubine Zhu to go to the Shangyuan Lantern Festival to guess riddles this year. What should I do if I do?" Zhao Ying suddenly asked.

If Liu Yi hadn't come back on the Lantern Festival, Zhao Huan's itinerary today was to follow Zhu Lian to visit the lantern festival and guess riddles.

Zhao Huan thought for a while and said, "Tell me about Concubine Zhu that it will take three or five days for the Bianjing Lantern Festival to go tomorrow. Today I will make a conclusion about the earth as a ball."

"This..." Zhao Ying hesitated, but looking at the excited official family, it was not easy to wipe out the official family's elegant atmosphere.

Zhao Huan looked at Zhao Ying's embarrassment and knew that Zhu Lian had carefully prepared this lantern festival trip. Zhao Huan asked with a smile: "Why do you ask Concubine Zhu, do you go see the big moon?"

"I'll go now." Zhao Ying left with a smile on his face. When he was ready to drive the car, Zhao Huan finally saw Zhu Lian dressed up carefully.

Zhao Huan was asking Liu Yi about the calculation process in the car, but it was not complicated. Liu Yi was a master of mathematics and he explained it very clearly and thoroughly.

Liu Yi looked at Zhao Huan who couldn't stop nodding, and was a little suspicious. Does the official really understand?

But he didn't want to ask randomly.

"The Military Weapons Court has arrived, the official family." Zhao Ying stopped the car and said to Zhao Huan inside the car.

Zhao Huan stepped out of the carriage, and the military weapon academy in front of him occupied an area larger and larger. Zhao Huan could see the growth of the military weapon academy over the past year.

The new equipment is not a simple process, and it is easy to have a large bed crossbow, but there are not many weapons with practical significance.

After Wanyan Zonghan was injured and Wanyan Loushi was killed in battle, there was no general who took the lead in charge.

This led to a large bed crossbow placing on Shanhaiguan, without a single arrow.

However, Zhao Huan was not anxious. Now the military weapons of the Song Dynasty were enough to lead.

Zhao Huan walked to a loft, which was built on the top of the mountain. The top of the mountain was imitated as the top of the water gazebo platform, which could be put together or closed.

The afterglow of the sunset shines on the houses in front of the observatory, and the red bricks and green tiles shine brightly under the sunset. Among the several houses in front of the attic, there are several busy officials from the Imperial Heaven Supervision Bureau.

Responsible for the maintenance and data collection of astronomical instruments such as armillary sphere, stroking instrument, silencing instrument, and other astronomical instruments.

Bianjing Royal Observatory

Zhao Huan actually wanted to remove the word "Royal", but the various equipment here invested in the treasury, and the word "Royal" was engraved on it in a bold manner.

But when he got here, Zhao Huan actually heard the sound of the Water Movement Gallery Station again and asked, "Zhao Ying, is this the hour of Xu? Is there an Gallery Station here?"

Zhao Ying nodded and said, "That's natural. The ambassadors of all states and prefectures across the country need to be adjusted here and give the prefectures time."
Chapter completed!