Three days later, outside the Hongwu Gate of the Imperial City, there had already been a sea of people gathered here, all of them stretched their necks to look at the Imperial City Gate, only to see an old man in a dragon robe sitting there under a Huangluo umbrella on the city gate, and there were many people around him, it was Zhu Yuanzhang, the founding emperor of the Ming Dynasty.

Zhu Yuanzhang picked up the teacup and took a sip, and then asked Zhu Biao next to him: "Li Jie is really confident that he wants to prove that the earth is like a ball in front of so many people." ”

"Father Qi, Li Jie actually has a hard time, because according to him, to prove that the earth is like a ball, you need a large enough field, and you can't use it in the imperial city at all, so you can only go to this square outside the imperial city." Zhu Biao replied with a smile.

"It's interesting, when will he arrive, and I really want to see what kind of means he uses now?" Zhu Yuanzhang also showed a curious look when he heard this.

"Your Majesty, I shouldn't be unsure of Li Jie, so I don't dare to come, right?" At this moment, I saw an official step forward and sneered, this person is Yuan Jianzheng, who made a bet with Li Jie, he also came to the palace early in the morning, but after waiting for so long Li Jie did not appear, this made him wonder if Li Jie had escaped?

"Supervisor Yuan is relieved, Li Jie is just going to fetch some things, and it is estimated that he will come soon!" Zhu Biao explained with a smile.

"Come on, come on, the old man saw them on the way here, and they will be there soon!" At this moment, an old man who was not amazing walked over with a smile, only to see that his skin was dark and full of wrinkles, and it was the evergreen Tang He among the founding heroes.

"Yo! Old soup, you also come to join in this fun? Zhu Yuanzhang saw his old friend Tang He and immediately laughed heartily, the old brother died and retreated, and the only person who stayed and trusted him was Tang He.

"Your Majesty, don't you know me, I'm just a good thing, where can I get together, the capital has been discussing this matter for a month, I don't want to miss it!" Tang He came to Zhu Yuanzhang with a smile and said, he is the prince of the country, and he has Zhu Yuanzhang's permission, so there is no need to salute at all, but Zhu Biao, who is the crown prince, wants to salute him.

As he was talking, he suddenly heard the sound of heavy wheels, followed by several large carts passing through the crowd, and then slowly stopped in the middle of the square, and then a dozen people dressed as craftsmen got out of the cars, and then immediately began to get busy.

Li Jie walked out of the convoy, then walked quickly to the city gate, and solemnly saluted Zhu Yuanzhang on the city gate: "See Your Majesty, Minister Li Jie is late, I hope Your Majesty will forgive your sins." ”

"No need to be polite, now you can always tell us how to prove that the earth is like a ball, right?" Zhu Yuanzhang also stood up at this time, holding the city wall with his hand and asked Li Jie below.

"I don't know the true face of Lushan, only because I am in this mountain. The minister wants to invite Your Majesty, what if you want to really see Lushan? Li Jie suddenly smiled and asked Zhu Yuanzhang rhetorically.

"This ......" Zhu Yuanzhang was stunned for a moment, and then replied, "Isn't there already an answer in the poem, I can't see Lushan clearly, that's because I am in Lushan, and if I want to see Lushan clearly, I naturally want to leave the mountain. ”

"What Your Majesty said is extremely true, the reason why we can't see the truth of the earth under our feet is because we are standing on the earth, and what we see is only a square land, and the only way to see the whole earth clearly is to leave the earth!" Li Jie reported very seriously.

"Boy, why don't I understand what you're saying, how can people leave the earth, is it possible that you want to fly?" Without waiting for Zhu Yuanzhang to answer, Tang He next to him asked very puzzled.

"Xin Guogong is right, I just want to fly, as long as I fly high enough, I can see the whole picture of the earth!" Li Jie raised his head and replied with a smile.

There are many ways to prove that the earth is spherical, such as by observing the changes of the stars, the reflection of the moon on the earth, etc., and even someone can calculate the circumference of the earth by calculation.

However, Li Jie didn't plan to use the above methods, in fact, he didn't understand it, but he knew a simple and crude method, that is, to fly up and see it directly with the naked eye, this is the so-called dimensionality reduction attack, even if it is a subtle calculation, it is not as real as seeing is believing.

"Ridiculous! Li Jie, you dare to bewitch the public in front of Your Majesty! Yuan Jian Zheng at the head of the city finally couldn't help but step forward at this time, pointing at Li Jie under the city and reprimanding.

In fact, it is not to blame Yuan Jianzheng, when the crowd around the square heard that Li Jie was going to fly, they were also in an uproar, and everyone showed a look of suspicion, although this kind of thing has appeared in the dreams of countless people, but no one has ever really done it.

"Li Jie, you...... You're not kidding, are you? At this time, even Zhu Biao, who had always trusted Li Jie, couldn't help but ask, he really couldn't believe that people could fly, and he also found that his father's face had become a little unsightly at this time.

"Your Highness, rest assured, how dare the minister joke at such a time, in fact, I have been preparing the tools for flying this month!" Li Jie said as he pointed to the craftsmen who were busy behind him.

"Are you sure you can really fly?" Zhu Yuanzhang also asked with a gloomy face at this time, he still had some confidence in Li Jie, but when he heard that Li Jie's method of proving that the earth was like a ball was actually flying, most of his trust in Li Jie disappeared at once.

"The minister is willing to guarantee with a head, and the minister will fly to the sky in person, and I also ask Your Majesty to promise to let Yuan Jian Zheng accompany the minister to fly to the sky, so that he can see the appearance of the earth with his own eyes!" Li Jie said solemnly again.

"Yes, I promise you!" Zhu Yuanzhang heard that Li Jie actually took a head guarantee, and his original disappointment was also a little relaxed, and whether he could really fly, and then he knew that if Li Jie really dared to bully the king, then don't blame him for turning his face and being ruthless.

"Your Majesty! Li Jie he ......"

Yuan Jian Zheng wanted to say something more, but was interrupted by Zhu Yuanzhang waving his hand: "Needless to say, you go down with Li Jie to see what he wants to do!" ”

Yuan Jianzheng didn't dare to say anything more, so he immediately agreed honestly, and then turned around and went down the city gate.

Li Jie also immediately turned back at this time, commanding the craftsmen to assemble the things he brought, and soon a huge airbag spread out a small half of the square, and then the hanging basket also began to be installed, which was the hot air balloon that Li Jie asked the Ordnance Bureau to make.

After a while, the hot air balloon was assembled, Li Jie personally stepped forward to light the fire, as the flamethrower was ignited, the heated air entered the airbag, and the convenient airbag slowly puffed up, and slowly floated in the air, which also caused the surrounding people to exclaim, and Zhu Yuanzhang and others at the head of the city also showed shocked looks.

"Unexpectedly...... It really floated! Zhu Biao looked at the suspended airbag and couldn't believe it, especially when the airbag began to float with the hanging basket below, which made him completely dispel his suspicions, it seems that this thing can really fly.

"I know, this is a large Kong Ming lantern!" Zhu Yuanzhang suddenly slapped the city wall and said excitedly.

"Yes, Your Majesty is wise, no wonder I thought this thing was a little familiar just now!" The soup next to him immediately agreed.

Zhu Biao and the others also showed a sudden look when they heard this, just now they had been shocked that this thing could fly, but they didn't know why, now when they heard the Kong Ming lantern, they all understood, after all, the Kong Ming lantern is something they can touch, although they don't understand the principle that the Kong Ming lantern can fly, but at least it is something they are familiar with, and it can also make them more acceptable.

Yuan Jianzheng, who was standing beside Li Jie, also opened his mouth wide at this time to look at the suspended hot air balloon, just now he was still suspicious, but now that the facts are in front of him, he can't help but not believe it.

"Is Supervisor Yuan ready, let's get on the gondola now, and then experience the first manned flight in human history together!" Li Jie smiled and said to Yuan Jian, for this hot air balloon, he has been almost sleepless in the past month, and he has consumed countless efforts before and after, and now he has lost ten pounds of weight than before.

And after making the hot air balloon, Li Jie also flew a few times outside the city, and found that the problem was directly modified, which experienced three major changes, countless small changes, and finally stabilized the performance of the hot air balloon, but during the test flight, it should have scared a lot of people, some people saw the hot air balloon in the sky and called the monster, but some people regarded it as a fairy, it is said that there were a lot of rumors in the capital for this.

However, before Yuan Jian Zheng could answer, he suddenly saw two people in the crowd of onlookers rushing out, and then came to the city gate to salute Zhu Yuanzhang above: "Qintian Supervisor Deputy Ma Hama, and Guo Zhenglin, the Lingtai Lang of the Five Senses, see Your Majesty!" ”

"Huh? What's the matter with you? Zhu Yuanzhang knew Ma Hama, and asked in surprise when he saw the two of them running over.

"Your Majesty, the minister begs Your Majesty to agree, let the two of us also accompany Li Si to heaven!" The two knelt on the ground at this time and pleaded, and Li Jie behind him also showed a look of surprise, he didn't expect these two people to take the initiative to ask for a hot air balloon, is this the legendary spirit of dedication to science?