"Fly! It's really flying! With the exclamation of the crowd, the hot air balloon that untied the cable also began to rise slowly, even if they knew that it was man-made, but there were still many ignorant people who knelt down to worship.

Soon the hanging basket was level with the head of the city, and Li Jie shouted at Zhu Yuanzhang and others at the head of the city at this time: "Your Majesty, the wind is strong in the sky, we may fly far away, and there may be some risks when landing, and I hope Your Majesty will send someone to chase the hot air balloon so that we can rescue in time!" ”

"I understand, you should be careful!" Zhu Yuanzhang also showed a rare excited look at this time, if it wasn't for the emperor, he would have been eager to board the hot air balloon and fly around at this time.

"The ministers are willing to take the lead, please rest assured Your Majesty!" Ma Hama, Guo Zhenglin, and Yuan Jianzheng, who were also in the hanging basket, also saluted Zhu Yuanzhang, but compared with the first two, Yuan Jianzheng's face was not very good-looking.

As he spoke, the hot air balloon rose again, and the speed of the climb became faster and faster, and the crowd under his feet became farther and farther away from the imperial city, although the weather was sunny today, the sun was also very good, and there was basically no wind on the ground, but as the altitude increased, the wind around him began to become more and more fierce.

"Brother Li, we really fly, the earth is under our feet, can we fly to the sun and the moon?" Guo Zhenglin excitedly grabbed Li Jie's arm at this time and asked, there were too many people just now, and he was embarrassed to show too much excitement, but now he finally let go.

"Brother Guo, it is possible to reach the moon, according to our observations, the moon is the closest star to us, followed by Mercury, Venus, and then the sun!" Mahama also excitedly said at this time, what he was talking about was the order of the celestial bodies set by Tomil, although obviously wrong, but it had a far-reaching impact on the Western astronomical community.

Li Jie was a little speechless when he heard the conversation between the two, just relying on a hot air balloon to fly to the moon and the sun, I have to say that the imagination of the ancients is still too rich, of course, this can't be blamed on them, but the limitations of the times, so that some common sense things in later generations are incomprehensible to people in this era.

"That's it...... Even if you fly so high, but the earth is still flat as far as you can see, don't be delusional! At this moment, Yuan Jianzheng, who had been huddled in the corner, suddenly spoke, but his face was pale at this time, and his hands were also tightly grasping the safety rope on the hanging basket, obviously frightened.

"This is where to go, but the height of about 100 zhang, if you want to see the true appearance of the earth, you need at least 10000 zhang or even more than 10,000 zhang, you do a good job, let's continue to improve the height!" After Li Jie finished speaking, he puffed up the fan, causing the flames of the vent to explode again, and the speed of the hot air balloon to rise again.

Watching himself fly higher and higher, Yuan Jianzheng's face became more and more pale, Ma Hama and Guo Zhenglin also felt an instinctive fear after being excited, but soon the two overcame their fear and began to ask Li Jie for advice on how to operate a hot air balloon, Li Jie was not stingy, and instructed the two to start working, after all, it was a bit difficult to operate a hot air balloon by himself.

Under the operation of a few people, the hot air balloon also rose higher and higher, and the temperature began to drop, especially the cold wind in the sky, which was like a steel knife scraping bones.

Fortunately, Li Jie had already prepared the cotton clothes, although Yuan Jianzheng was stubborn, but he couldn't stand the cold at this time, so he immediately took the cotton clothes and put them on, and at this time, Guo Zhenglin suddenly pointed to the horizon in the distance excitedly and said: "Look, the earth has an arc!" ”

Li Jie and Ma Ma heard the prestige, and saw that the horizon in the distance really appeared a slight arc, but this arc was very inconspicuous, and if you didn't observe it carefully, you couldn't detect it at all.

"Hmph, that's it...... Even if there is an arc, the earth is like a chessboard, not that the earth is really as smooth as a chessboard, we have long found that the earth has some ups and downs, and a little arc can't prove anything at all! Yuan Jianzheng was still stubborn, of course, if his face was not so pale when he spoke, it might be more convincing.

"Hehe, it seems that Yuan Jianzheng is still not convinced, this arc is not obvious, that is because our altitude is still too low, continue to climb harder, and when we reach a certain height, we will definitely be able to see more clearly!" Li Jie smiled calmly.

Ma Hama and Guo Zhenglin had overcome their fear of heights at this time, and they also wanted to fly to the moon, so they were also full of energy at this time, and the flames from the fierce fire oil spewed out more than a zhang high, making the hot air balloon suddenly lift again, but this also made the hanging basket shake, and the frightened Yuan Jianzheng grabbed the rope even more.

As the altitude of the hot air balloon increased, the curvature of the horizon became more and more obvious, and Li Jie had been observing the surrounding situation, they had already flown out of the range of Nanjing City, and were now drifting in the direction of a little north-east.

In addition, Li Jie also found a phenomenon, that is, at different altitudes, the wind direction is actually different, for example, when the take-off began, the wind direction was still northeast, but now it has become southwest, and the further up, the wind direction may change somewhat.

Li Jie didn't have an altimeter in his hand, and he didn't know what altitude he had risen to now, but he should have reached a few kilometers, because he already felt some difficulty breathing, according to the regulations of hot air balloons in later generations, flying more than three thousand meters, he must be equipped with oxygen, otherwise it may be dangerous.

But now there is no oxygen, and Yuan Jianzheng has not admitted defeat, so he can only continue to increase the altitude, according to the experience of Li Jie's later generations in the airplane, generally to the height of the plane flight, and there is no cloud cover, you can see that the earth obviously has an arc, but the height of the plane is generally more than 10,000 meters.

In fact, the maximum altitude reached by the hot air balloon in later generations was more than 30,000 meters, which has exceeded the flight altitude of the aircraft, but the hot air balloon is closed and equipped with other powers.

In addition, there is an unmanned hot air balloon, which can fly up to more than 40,000 meters, and also take a photo of the earth, which can clearly see that the earth is spherical, but this unmanned hot air balloon has also reached the limit, and it exploded after taking a photo.

However, Li Jie was a little worried, the hot air balloon he made can be said to be very simple compared to later generations, not to mention flying to an altitude of 30,000 or 40,000 meters, it is very difficult to reach the height of the aircraft, especially since he has no oxygen and is not a closed gondola, so even if the hot air balloon can fly, they may not be able to stick to that height.

"Look! The curvature of the earth is becoming more and more obvious! Compared with Li Jie's worries, Guo Zhenglin and Ma Hama were full of interest, pointing to the horizon of the earth and saying loudly again.

Yuan Jian was looking at the curvature of the earth, and his eyes also showed a little confused, as if he had been shaken, and when his gaze moved downward, seeing the shrunken mountains, rivers and cities on the ground, his expression became extremely frightened, obviously he still couldn't overcome the fear brought by the fear of heights.

"The height is not enough, keep rising!" Li Jie immediately commanded again, but as soon as the words fell, a strange wind suddenly blew, causing their hanging baskets to swing sharply, and several frightened people grabbed the rope to death, and Yuan Jian Zheng screamed regardless of his identity, and several people fell into a great crisis for a while.