With the strong support of Qu Chang and others, these 1,200 people were able to withdraw and successfully enter through the entrance at the bottom of Posedonia City.

When the 1,200 people successfully entered the entrance, Qu Chang and the people who stayed behind turned their heads and blessed: "The next thing depends on you!" ”

After entering the hole at the bottom of the city of Poseidonia, the group began to move rapidly upwards. It didn't take long for Tianxuan to raise his head, and as far as his vision could reach, he saw the Heavenly Pillar in the city. He gritted his teeth, and then ordered: "Rush forward!" ”

Under Tianxuan's order, everyone began to float up desperately. However, he did not rise for long before he suddenly noticed that the color of the sea water near the exit had suddenly changed from sea blue to sky blue, forming a clear boundary between shades of color.

At first, Tianxuan didn't care, and went straight up, but when he reached the color dividing line, he suddenly found that he was stuck and couldn't go up.

"Hey, is there a barrier up there, why can't you go up?" Tianxuan looked around when he was wondering, and found that Qianjun, Feixing and the others were already far above him, and they were almost in the city.

"What's going on?" Seeing this scene, Tianxuan understood that it was his own problem, so he desperately floated up, but no matter how hard he tried, it was useless, and he couldn't go up as if he was pressed by a jack on his head. He glanced around again, and saw that there were quite a few people stuck in this position besides himself.

"Brother Xing, Brother Jun. I'm stuck! Seeing that the situation was not good, Tianxuan hurriedly transmitted brain waves to Feixing and Qianjun.

After receiving Tianxuan's call for help, Feixing and Qianjun hurriedly returned downward, and soon came to a place less than two meters above Tianxuan's head, and then stopped above the color dividing line.

After seeing Feixing and Qianjun coming, Tianxuan sighed and said, "You guys are finally here!" ”

Feixing smiled and said, "What's the matter, Tianxuan, why don't you come up?" ”

"I, I'm trapped! I can't go up! Tianxuan said anxiously.

"Huh? How are you feeling right now? Qianjun asked.

"I felt like there was a barrier up there, and I tried to break through and was quickly bounced back like a spring." Tianxuan said in detail.

"Hey! Let me give you a hand! As he spoke, Qianjun stretched out his hand to unleash the gravitational vortex.

Then, Tianxuan felt a violent vibration, and suddenly broke through the barrier and came up.

"Hmm! ......" Tianxuan sighed, and was about to say something, when he suddenly felt as if he had stopped on the ground. So, he said to Qianjun: "Brother Jun, it's okay, you don't have to hold me up, I can stabilize it myself." ”

"What are you talking about?" Qianjun asked strangely.

Hearing Qianjun say this, Tianxuan immediately felt weird, and then asked, "You didn't hold me, so why do I feel as if I am stopped on the ground?" ”

At this time, Qianjun smiled and said, "Oh, you are now on the bottom of the liquid sea." ”

"Liquid seabed?" Tianxuan's eyes immediately widened when he heard this, and he was surprised but still surprised.

"That's right! Because the stress surface of the spherical barrier we make is relatively stable, it is generally difficult to break through the liquid seabed, and naturally it is difficult for you to go down. Qianjun explained.

So, in order to prove the bottom of the liquid sea, Tianxuan also deliberately shook it, and then wrapped his spherical barrier like on a trampoline, jumping and jumping, quite elastic. After that, a smile appeared on the corner of his mouth and sighed: "This liquid seabed is really good, not only can't it fall, but it is also very elastic." What the hell is going on? ”

"The sea here forms a density cline."

"Density Thermocline?"

"Well, yes. There is a great difference in the density of seawater between the surface and the deep layer. The low-density seawater will accumulate on the high-density seawater, which will be light at the top and heavy at the bottom, so that the seawater will be distributed in layers. Between the upper and lower layers, a barrier is naturally formed, which is called the density cline. ”

After listening to Qianjun's explanation, Tianxuan had a general understanding of the so-called density thermocline, but he couldn't fully understand it. At this time, he suddenly remembered the dictionary that the checker had given him. So, in order to act better later, he hurriedly took out the dictionary that was hung on his body and was pressed into a two-dimensional sheet, and then used force to quickly restore it to its original appearance.

"Looks like you're starting to master your abilities!" Feixing said with a smile.

"Where, so-so!" Tianxuan responded, and immediately shouted "iki language", and then the dictionary quickly turned the pages.

Later, Tianxuan looked up the information about the density cline from the dictionary: in the holographic image from the dictionary, a submarine named Seawolf appeared, which was on a mission to dive. However, when the submarine descended to a few hundred meters, a clearly colored boundary of the sea suddenly appeared. Immediately afterward, the submarine was stuck between the boundaries and could not move.

After a while, the submarine began to fill with seawater to increase its weight, and after a few moments, when the weight reached a certain level, the sea wolf broke through the boundaries of this layer of liquid seabed and sank to the bottom of the sea.

At the same time, the dictionary also explains that the density of sea water varies from place to place. As a rule. Seawater with high temperature is less dense, while seawater with lower temperature is denser. Seawater with low salinity is less dense, while seawater with high salinity is denser.

If there are two densities of seawater in a sea area at the same time, then the less dense seawater will accumulate on top of the denser seawater, so that the seawater is distributed in layers. This creates a barrier between the upper and lower layers, called the "density cline". Some of these "density cairclines" are several meters thick. This stable "density cline" divides the seawater into two types of water masses, one at the top and the bottom of the thermocline, with the thermocline as the boundary.

Moreover, the density cline also has its own unique places, such as the submarine is hidden under the cline, it is not easy to be detected by the enemy ship's sonar and evade tracking; In addition, it can be moored on the cline to reduce fuel consumption.

After reading the introduction of the density jump, Tianxuan closed the dictionary, recompressed the two-dimensional sheet of the city and hung it on his waist, and sighed, "So that's what happened. ”

"Got it now?" Qianjun asked.

"Got it! We can move on! Then, after Qianjun helped his stuck, his companions break through the liquid seabed, and the group floated upwards with all their might.

However, as he was about to leave the passage of the density hop, Tianxuan noticed that another layer of distinct colors had appeared on it.

"Brother Jun, there seems to be another density layer on it." Tianxuan said, pointing to the boundary between the azure sea and the light blue water.

"Hmmm! Let's find out. With that, Qianjun and a few super generals floated up to find out.

After surfacing the entrance, hundreds of mermaid guards discovered the invasion of Qianjun and the others, but unfortunately they were quickly killed before they could report it.

"It's all solved! Come up. After finishing the guards, Qianjun beckoned the people below to hurry up.

After breaking through the second density leap, Tianxuan led everyone to quickly eliminate all the guards on the first layer with lightning speed, and began to float towards the second layer of this concentric circle city.

However, after surfacing the second layer, Tianxuan found that the environment of the second layer and the first layer had changed greatly.

"What's wrong, Tianxuan?" Qianjun saw Tianxuan stunned for a moment, and then asked.

"Huh!" Tianxuan looked at the passage behind him and said, "Have you noticed, when we were on the first floor, we were surrounded by seawater, and now outside of those criss-crossing waterways, there is air. These Atlanteans used the density cline to make the city a land in the sea. ”

Qianjun looked around, nodded and said, "That's true!" After all, the Cupids used to live on land, and since the Atlanteans inherited their technology, they must take some protective measures. However, I didn't expect them to use this way to separate the air from the sea. ”

"What a masterpiece, if I could, I would have liked to have avoided destroying the city as much as possible!" Tianxuan couldn't help but sigh.

"I hope so! Just capture their leader, Poseido, and it's all over! Qianjun said.

"Hmmm! Let's go! ”