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……

Twenty examiners, each with their magical powers, jumped on the star tree suspended in the sky.

This starcha that resembles a long whale is called Kunpeng Xingcha, which is a customized version of Kunpeng City.

It is more than 100 meters long, and it is only a human-level star.

Two huge wings stretched out from both sides, like clouds in the sky.

It looks like a wing, but it's actually a Xunfeng sail.

A rune array of brilliance flashed across the wings, and suddenly there were pieces of armor that resembled fish scales, covering the entire wings.

The shaking of the ctenophores with the wind seems to be really the feathers of a pair of wings of a huge pengyao, absorbing the power of Xunfeng while continuing to escort the growth rate of Xingcha.

[I have known an old book friend for ten years to recommend to me to chase books, @

It's settled.

Speeds between Mach 1 and Mach 5 are called supersonic; Speeds above Mach 5 are called hyperhypersonic.

In the end, Xingcha was able to fly without breaking through hypersonic speeds.

Li Sui'an stretched out a finger and dipped some saliva in the air, clearly feeling that the temperature had risen.

Walking to the edge, curious reached out and touched the shield.

"Wave~"

A halo of light spread out from the point where the finger touched.

He didn't expect such a violent sound to reverberate.

And all the people who were meditating peacefully on the deck turned their eyes to him in unison.

"What are you doing?"

The voice of the Thousand Households Chen Gong suddenly sounded behind him.

Li Sui'an was startled, he didn't notice anyone approaching just now.

As soon as he turned around, he happened to meet the blood-eyed crow on Chen Gong's shoulder.

The crow tilted its head humanely and looked Li Sui'an up and down.

His heart suddenly sank, and he bowed down and said, "Lord Hui, I just want to test the temperature change when Xingcha breaks through the limit of the speed of sound."

Chen Gong's voice couldn't hear the likes and dislikes, "Then have you ever measured it?"

Li Sui'an was slightly silent, but still said, "...... It's a little bit of a gain."

"Oh, tell me about it. Anyway, it's still a long way to go, so I don't mind hearing about it."

Li Sui'an had no choice but to bite the bullet and say, "When the speed of the Xingcha broke through the speed of sound, there was a sound barrier. At nearly twice the semisonic speed, the temperature rises significantly. The Xunfeng Sail reacted violently, and the energy output of the rune array continued to increase. After that, the temperature continued to rise with each layer of velocity breached. Even if it is protected by a shield, you can still feel the ...... clearly."

"You just said the speed of sound? Sound impediment?"

Chen Gong suddenly interrupted him and asked a question.

Li Sui'an glanced at the men and women on the deck, and even the lantern bearers and night watchmen who were guarding him also looked at him.

Helplessly, I had to explain the speed of the sound a little more.

"The essence of sound is only a ripple (mechanical wave) that propagates in a medium, and it travels at different speeds in water, in the air, and in the earth. Different mediums, temperatures, and pressures all have an impact on the propagation velocity. It is usually the fastest in solids, the second fastest in liquids, and the slowest in gases."

"There are many ways to test the speed of sound propagation. The speed of Xingcha exceeds the speed of sound transmission, and if the sound cannot catch up, it will naturally produce sound barriers."

"I haven't been exposed to Xingcha production, but I suspect there should be a set standard for this. I set the speed at which sound travels through the atmosphere at the basic speed of sound."

(PS: The density of the atmosphere in the mountains and seas is inevitably different from that of the earth.) Talking about Mach without talking about height is playing hooligan, Mach is a unit of speed, and Mach 1 is not always equal to 340 m/s. ）….

Chen Gong was very surprised, and said thoughtfully, "Since the speed of the voice can't keep up, why can you and I still speak?"

"My lord, this is a relative situation. How it works,...... It still needs to be studied." He didn't want to explain the theory of relativity.

"You go on. What does this have to do with the temperature at which you test the shield?"

"Yes, sir."

"Sound travels at different speeds in different media, temperatures and pressures. The higher the density of the medium and the higher the temperature, the faster the sound propagation. The obstacles to the flight of the star also include sound, air, and friction and heat."

"The higher the altitude, the lower the temperature, and the thinner the atmosphere."

"I think if the star can fly to a higher area, it might be able to go faster."

Hearing this, Chen Gong took a serious look at him and said, "Do you know that if you go any further, you will encounter the Nine Heavens Gangfeng? The wind spirits and wind monsters in the Nine Heavens Gang Wind will not be polite to you."

Walt?

Li Sui'an raised his head, the sky was clear, there were only a few white clouds, where did the Nine Heavens Gang Wind come from?

This clearly offends his intellectual blindness

area.

At the same time, he also realized that much of his knowledge on earth could not be blindly copied.

Perhaps he is very knowledgeable in some aspects, but in terms of seeking truth from facts and studying in combination with the actual situation, I am afraid that even Hu Boji is not as good as him.

Just when he didn't know how to answer, Chen Gong said again, "But the sky should be safe, you can try."

With that, he waved his hand behind him.

Immediately, someone shouted into the cockpit of the star, "Raise the height, ten thousand!"

"Yes."

Aung Aung Ang~

The Kunpeng Star suddenly made a strange noise, really like the neighing of a long whale.

The huge halberd on the head of Xingcha pierced the sky and raised its head suddenly.

Everyone on the deck leaned suddenly, barely standing still. Immediately a jack fell before he stood firmly.

Li Sui'an grasped the masts and reins on both sides very carefully.

Chen Gong put his hands behind his back, looked up at the sky, and remained motionless.

That's 33,000 meters in the sky.

By Earth standards, this should be the troposphere.

Clouds, rain, snow, hail, etc., all occur in this layer.

Even in this world, it is a rare experience to be able to reach this height now, and Li Sui'an immediately concentrated on observing.

At the same time, looking at the distant sky, he wanted to see the edge of the planet.

It's a pity to look lonely.

Even at a high altitude, they are still flying among the mountains, and they can't even see some of the higher peaks, let alone look at the edge of the planet.

This world is far bigger than you imagined.

But it can still be roughly judged that the Mountain and Sea Realm is not a strange continent floating in the universe, but also an extremely large elliptical sphere.

Therefore, it is impossible to see the edge of the planet from a thousand feet in the sky.

However, at this height, the tallest Optimus Prime iceberg due north of the Canopy Mountain Range finally revealed the upper half of the clouds that had not dispersed all year round.

It turns out that when I used to bask in the sun, I could only look at the mist from afar, but it was only at the foot of the mountain.

The upper half of Optimus Prime is covered with glaciers, bathed in golden sunlight, forming a golden color, like a holy mountain! ….

It's so big that I don't know how many miles high.

Li Sui'an had to suspect that the peak of that mountain range was going straight into the universe.

"Someday, I'm going to climb that mountain."

Li thought with peace of mind.

The height of 10,000 zhang is not enough compared to large peaks, but compared to those ordinary peaks on the earth, it is more than enough.

Looking down from the sky, the peaks look like low dirt slopes.

Many people looked at the pale ground, their throats were surging, some panicked, and even their legs trembled, and they unconsciously walked to the center of the deck, away from the edge of the star, afraid of falling.

In ancient times, the sky was a forbidden place for the gods.

Today's human beings have repeatedly broken through the limitations of high altitudes, but they are limited by the limitations of knowledge dissemination, which is still only seen by a very small number of people.

"Fear of heights!"

Li Suixin held back a smile, "It's a good thing I didn't."

He grabbed the railing and looked into the distance.

The view here is amazing.

As far as the eye can see, there are no peaks in sight, and there are more than a dozen of them.

But at this altitude, the air pressure has also been further reduced, and the speed of Xingcha has indeed increased further, about 1400s.

"Keep rising!"

Chen Gong's spirit was shocked and continued.

"Yes!"

shouted from the cockpit behind him.

Li Sui'an was silent.

This mysterious envoy of the Thousand Households of the Heavenly Department seems to be calm in appearance, but his heart is even crazier than him.

The star rose again, 13,000 zhang, 15,000 zhang, 20,000 zhang, and it was still rising, until it reached a height of 25,000 zhang.

"Hum~"

The speed of the star soared suddenly.

He took a deep breath, and his heart beat a few times quickly, and the uncomfortable feeling of lack of oxygen calmed down.

Stratosphere?

Why are there still mountains around you?

On Earth, it would have entered the stratosphere a long time ago, but in the realm of mountains and seas, it is still far from the stratosphere.

The 100-meter-long star chariot flies between the towering mountains like the pillars of the sky, like an incalculable sparrow.

The sight of the distant sky began to become a lake, as if the whole world was shrouded in a layer of dark yellow light.

However, it didn't take long to fly.

In the sky, where there was nothing at all, the wind suddenly became violent, and a layer of fiery red qi appeared on the protective cover.

A flash of electricity began to flicker on the wings of the star.

"My lord, I've reached the limit, and I can't go up anymore."

A subordinate Baihu spoke up.

Chen Gong was a little unsatisfied, nodded, and was about to give the order to descend, when something suddenly changed ahead.

I saw a translucent monster suddenly rushing down from the sky.

In terms of size alone, it is hundreds of meters long, several times larger than the Kunpeng Starcha.

"Oops, it's the Nine Heavenly Gangfeng Octopus!"

"Descend!"

Without Chen Gong's orders, Baihu directly ordered.

The Kunpeng Star immediately fell ninety degrees.

Everyone was a little panicked, where did they still care about being handsome, and they were looking for a place to catch it.

One of them didn't grasp it steadily, and it fell directly on the shield, and bounced back, clutching the deck in embarrassment.

The Gangfeng eight-clawed wind monster chased after it and rushed straight down.

The Kunpeng Xingcha dodged quickly in the air, narrowly avoiding tentacle attacks several times. ….

Chen Gong just looked at the eight-clawed wind monster, and didn't mean to make a move at all.

Xingcha fled in embarrassment, falling straight to the bottom of 10,000 feet, and the monster let out a roar of reluctance.

Infinite storm-like blades of wind erupted from its mouth and struck the shield, sending layers of energy debris scattered like snowflakes.

The star chariot continued to descend until it was five thousand zhang in the air, interspersed back and forth among the mountains, and when it saw that it could no longer catch its prey, it was unwilling to stop the pursuit, flicked its tentacles again, and flew towards the nine heavens.

Everyone breathed a sigh of relief at the right time.

Chen Gong seemed to be accustomed to it, and asked Li Sui'an, "Have you ever learned the Formation Dao?"

Li Sui'an said: "My subordinates are new to the formation path, but they have no good teacher, so they can only figure it out by themselves."

"Hmm~ After completing the assessment, there will be a Heavenly Machine Department that specializes in studying the formation path, you can consider it."

"Thank you for your advice."

"Hmm."

Chen Gong just said one more word, and entered the cabin with his hands behind his back.

The rest of the people looked at Li Sui'an, there seemed to be something more in their eyes, but no one came up to talk.

Even if it is an exchange, it is not too late for everything to be finalized.

Three hours later.

The star chariot flew smoothly among the mountains.

The calm appearance of the Qianhu Lord no longer took risks, and he did not encounter any danger along the way, even if there were occasional high-altitude birds that jumped out, in front of the characters of the Yugang realm such as the Qianhu Envoy, they were all as vulnerable as a paper lake.

Chen Gong didn't even show the attack of the Divine Soul Technique, but the extreme speed and strength of his gestures made the eyes of everyone on the deck glow with envy.

Finally arrived at the destination.

Wind Tunnel.

It is one of the seventy-two secret realms of the Northland.

It is located in the south of the Optimus Prime Peak of the Tianpeng Mountains, connected to the cold air of the North Sea, and the perennial wind does not disperse, and it is rarely uninhabited.

The full name of the Arctic Plain Road is the North Sea Ice Plain Road, which is connected to the North Stygian Sea.

Legend has it that the Yin Wind Cave is the place where the Northern Hell Supreme banished the Northern Hell Sinful Spirit.

Li Sui'an read the Taoist Sutra, which contains many legends about the supreme of the ancient Northern Underworld.

When we arrived at our destination, it was still heavily guarded.

The Yin Wind Cave is not big from the outside, it is about 100 zhang wide, and it is composed of countless small wind holes.

The surrounding area is rocky and forested with ancient trees, but there are many damaged ancient buildings outside the cave.

From time to time, you can see some dilapidated huge temple complexes, and even Buddhist temples, Taoist temples, etc., all show that there were once people living here.

The star fell in the square.

Someone immediately greeted them and brought everyone to the stone platform outside the Yin Feng Cave.

Everyone stood in the arena and listened attentively to Chen Gong saying, "Among the martial artists, those who have the qualifications of Divine Soul Martial Artists are one in a million."

"But among the Divine Soul Martial Artists, there are also three, six, nine and other qualifications. One to three of them are superior qualifications; Four to six grades, medium qualifications; And the seventh to ninth rank are inferior qualifications, depending on the divine soul and spirit species."

"Legend has it that above the first grade, there are still the best divine soul species. But this legendary supreme qualification has not appeared for a long time since the arrival of the Black Tide."

"There is a soul test stone here, people who can test the qualification of the divine soul, just put their hands on the stone, they can test the qualification of the divine soul."

"Before entering the Yin Wind Tunnel, let's test your qualifications."

After Chen Gong finished speaking, he stroked the black crow and stopped talking.

Immediately, there was a military general, who stepped forward and commanded everyone to test their qualifications in turn.

I don't know how many times the test stone has been touched, and the surface is smooth and starched. But it was still pitch black, as if it was connected to the whole mountain.

The general casually ordered, "You're the first to come."

The person who was the first to be called, named Hu Chao, asked very seriously, "This general, how do you measure this qualification, is it just to press your hands on it?" Is there anything I need to pay attention to?"

"Press your hands on it, and if you have the Divine Soul qualification, the Soul Measuring Stone will glow. Different brightness of light means different qualifications."

Hu Chao pressed his hands up as he said, and his face immediately showed a distracted expression.

Everyone immediately stared at it with wide eyes.

I saw that the originally black stone actually emitted a dazzling purple light, and the light became more and more vigorous.

Everyone immediately discovered the secret.

The brightness under the stone was divided like a lattice.

A moment later, I heard Hu Chao let out a scream, breaking free from his state of trance, and two rays of light lit up on the stone.

"This ...... Are my qualifications good or bad?"

Hu Chao looked at the test results with a blank face.

False blessings