Cheng Yaojin said with disdain: "how hard can it be to deal with a mere Tubo? Can it be better than the Turks? Ziyou, don\'t deceive me!"

"Uncle Cheng, when it comes to the combat effectiveness of Tubo, it\'s not as good as the Turks, and it\'s not as good as my Tang cavalry." Li forgot to worry replied.

Strictly speaking, the fighting capacity of Tubo is not as good as that of the Tang army.

In history, the first war between Tubo and the Tang Dynasty broke out in Songzhou with the Tang army after Tubo annexed Tuyuhun in the autumn of the 12th year of Zhenguan.

Before the big army led by Hou Junji, the main force of the Tang army, Niu JINDA, as the vanguard of the Tang army, had defeated the Tubo army.

Fearing the Tang army, Songzan Ganbu led the Tubo army to withdraw from Tuyuhun, Dangxiang, brandqiang and other places, and sent envoys to apologize.

After the Tang Dynasty and Tubo, during the wartime and more than 200 years, the main problem of Tubo was that once Tubo was defeated, it would immediately return to the plateau.

The Tang army attacked the Qinghai Tibet Plateau three times, but all suffered failures due to plateau reaction and weather.

This formed that Tubo could attack Datang and return to the plateau after losing the most, but Datang was difficult to counter attack Tubo.

It has always been only a thousand days to be a thief, and there is no one to prevent thieves. Therefore, it is normal for the Tang Dynasty to suffer losses from Tubo.

Li Er and others naturally don\'t understand these situations.

Cheng Yaojin didn\'t understand and asked, "since that shit Tubo can\'t beat my Tang iron horse, why are you so worried? What do you say Tubo is a trouble in my Tang Dynasty? Are you kidding me?"

Li forgot his worries and was speechless. He could only point to the plateau on the map and explain, "Uncle Cheng forgot? I said before that the Qinghai Tibet plateau where Tubo is located is more than 3000 meters high?"

"Well, so what?" Cheng Yaojin still didn\'t understand.

"Does uncle Cheng know the miasma?"

The miasma in Li\'s mouth actually refers to altitude sickness.

As early as the Han Dynasty, China was aware of the existence of altitude sickness, which was called miasma or miasma.

In the humid and hot environment of the southern jungle, the toxic gas produced by the decay of animals and plants is also called miasma.

Although the name is the same, in the mouth of doctors, the diseases corresponding to malaria in different regions are different.

Cheng Yaojin and others were slightly stunned when they heard the speech: "what do you mean, there is miasma on the plateau?"

Li Qieyou nodded affirmatively: "to be exact, it should be called altitude reaction, which is also what Shizun taught me."

Li Er asked, "Ziyou, tell me in detail what altitude sickness means?"

"Uncle, you have seen the Academy hemispheric experiment that my nephew did today. You should be able to understand what my nephew said before. In the air, it is not empty."

Li Er nodded: "yes, I understand this now. I remember you said at the Tai Chi hall that air is mainly composed of oxygen and nitrogen, and oxygen is the root of our life."

Li Qieyou admired Li Er\'s good memory. Before, he popularized science in front of all officials.

He was not in a hurry to answer Li Er\'s questions, but ordered the old housekeeper Li Heng to get a crystal cup.

In the Hangzhou Museum of later generations, there is an exhibit. After seeing it, many tourists will think that the museum has made a mistake and took a modern glass as an exhibit.

In fact, the glass with the same style as the modern glass is the crystal cup of the Warring States period.

During the Warring States period, the crystal cup can be polished manually, and so can the Tang Dynasty.

The crystal cup in Li\'s house was made by the craftsman who asked him to be the supervisor according to the shape of the glass of later generations.

He took out the fire fold, lit a candle, put it on several tables, and inverted the transparent crystal cup on it.

"Uncle and gentlemen, the oxygen in the air is the root of our breathing and survival. And the candle also needs oxygen to burn. If the oxygen in the cup is exhausted, the candle will extinguish itself."

With Li\'s words, the candle flame in the crystal cup swayed a few times and went out by itself.

This is just a very simple combustion test, but Li Er and others couldn\'t help staring at each other and looked incredible.

Cheng Yaojin can\'t wait to pick up the crystal cup, relight the candle, and then buckle the crystal cup upside down.

Dozens of seconds later, the candle went out quietly again.

"Zhiniang thief, there is such a thing!" Cheng Yaojin subconsciously grew up and took a few deep breaths. He was afraid that he would die because of lack of oxygen.

He turned and looked at Li Qieyou: "Ziyou, what kind of oxygen is amazing! But what does it have to do with the altitude reaction you just mentioned?"

Li forgot to worry and said with a smile, "Uncle Cheng, I\'m afraid you don\'t know. The distribution of oxygen in the air is also different. The higher the altitude, the thinner the oxygen is. Even to the extreme altitude, we can\'t breathe at all. We can die in a moment."

"Apart from the extremely high terrain, the biggest problem with the Qinghai Tibet Plateau is that the oxygen is very thin. If ordinary people enter the plateau, they will suffer from symptoms such as headache, fatigue, palpitation, shortness of breath and dyspnea, and even lose their sexual lives."

He smiled and looked at Cheng Yaojin: "Uncle Cheng will be short of breath and weak if he goes to the plateau. He can\'t give full play to his skills. In this case, how can he fight the Tubo people?"

Li Er and others looked at each other when they heard that there were such wonderful stories in the world.

Fang Xuanling frowned and asked, "Ziyou, aren\'t those Tubo people afraid of altitude sickness?"

Li forgot to worry and nodded: "Mr. Fang, Tubo people have been used to living on the plateau since they were young. Although they will also be affected by the altitude reaction, the impact is much smaller. Therefore, if there is a war between Tubo and our Datang, even if they lose, they will just return to the plateau. We can\'t help them at all. In this way, it is equivalent to that Tubo is already in an invincible position."

Li Er\'s face is as heavy as water at the moment: "Ziyou, if it\'s true as you said, this Tubo is really a problem in my heart!"

Fang Xuanling, Gao Shilian and eldest sun Wuji also nodded one after another.

Such a potential enemy makes them feel very unhappy when they think about it.

With geographical advantages, only Tubo could attack Datang, but Datang could not attack the hinterland of Tubo.

In this way, didn\'t the Tubo army come and go whenever they wanted? Even if you can\'t fight, you can return to the plateau, recuperate and lick the wound.

If Datang is attacked passively, it can only invest huge human and material resources to strictly prevent and defend in the border area.

Looking at the map, Li Er and others were even more worried.

Close to Tubo, but where the Tang Dynasty is rich, Yizhou and other places. Once the Tubo army attacks Datang, Yizhou will suffer first.

After all, Gao Shilian has been the governor of Yizhou for many years. Seeing this situation, he is naturally worried.

"Your Majesty, if it is true as Ziyou said, Tubo must be protected!"

"Yes, how can others snore beside the bed! If Tubo is not eliminated, my Tang Dynasty will be like a lump in the throat? Your majesty, this is no small matter!"

Several big men were anxious and spoke to Li Er one after another.

However, Cheng Yaojin suddenly looked up and laughed, which made everyone look sideways. He didn\'t understand why the old rascal was crazy again?