Blue Star

"At this height, the length of the climbing rope is not enough. Daoporing, Mimir, give me your rope too." Gu Li tied a point on the edge of the cave entrance, took the rope handed over by the two, linked it and threw it to the bottom of the cave go down.

He pulled hard at the place where the binding was tied, and after confirming that it was secure, he said, "I'll go down to find the way first, and you wait for me up there."

Dao Porling looked anxiously, "Maybe there are experimental subjects under here, don't you want to look again?"

Gu Li tied one end of the rope around his waist, closed the buckle and tightened the climbing rope, put his feet against the edge of the hole, and his whole body was in a semi-inclined state.

"I threw a piece of lighting crystal mine down just now, and it didn't seem to make any movement."

After he closed his mouth, he took a deep breath, loosened and tightened his hands quickly, and jumped down for a while.

The grooved rock blocks trampled by military boots dropped a small amount of stones, accompanied by sporadic impacts, and finally fell into the underground channel.

He stabilized his balance and looked up at Iris who was standing at the entrance of the cave.There is no obvious attack posture to be sure, and the way he went down is fairly safe.

When he reached a position of about 15 meters, he looked around again with the light from the ring.Part of the rock wall is shaped like a fixed waterfall, and after being illuminated, it reflects a shell-like crystal.

Turn the ring so that the beam is directed downwards.

The water flow in the underground river channel is not urgent, but the depth is unpredictable.The water looks clear, but the bottom of the water is pitch black. It seems that someone has painted a layer of black paint on the bottom of the water, but it also seems to have accumulated a layer of black silt.

When he was about to fall to the ground, he unbuttoned his collar and shook the cloth on his chest to remove the heat.

The temperature at the bottom of the cave is higher than that at the top. Although it is sweltering, the good thing is that few creatures want to come here.

Pick up the lighting crystal ore thrown down earlier, and expand the light source to check both sides of the river.

Not just creatures, even plants and slime molds didn't grow a single one.However, some human utensils can occasionally be seen on both sides of the river, such as severely oxidized broken mechanical doors, or some broken ceramic bowls.

The monsters mutated after being sent into the dungeon, so it can be seen that they should have lost their minds after they escaped from the dungeon, so the murals are unlikely to be left by these monsters.

He raised his sleeve and wiped the sweat off his chin, and checked the water flow near the edge of the river.Under the illumination of the light, he finally saw clearly what was deposited on the bottom of the water.

It's really interesting, the whole looks like kerosene, but there are many places that are condensed into lumps, and there are many vertical V structures in the shape of a hemisphere like a hedgehog.

Standing up, he shouted to the three people on the height: "You can come down, you can go out along the water."

The rope itself was 16 meters long, and he took two, but almost half of the last climbing rope was dragged on the ground.

35 meters from the ground, if he was in a town at this height, he would choose fluorite to float without hesitation.But for now, it's better to be safe.

It was Iris who came down first. After helping Mimiel, who was not very flexible, he landed, and then extended his hand to Daoporing friendly.

But Dao Porling was still angry, as if he didn't need help.But Iris's eyes looked very sincere, and after being rejected by him twice, he still raised his hand to help him.

Thinking of what Gu Li said that the mermaid's behavior cannot be judged maliciously in a human way, he said, "For Gu Li's sake, I won't argue with you for the time being."

After all, he let go less than two meters from the ground, and was about to pull Iris' hand to help him.

But he didn't expect that the fish suddenly put away his fawning face, pretended that nothing happened just now, turned around and walked towards Gu Li.

Dao porphyrin, who had no support point, fell to the ground in a panic, but fortunately, the height was not high, and he did not cause any injuries.Patting his robe to straighten the crooked glasses on his head, he complained to Gu Li with his waist: "This fish is getting worse and worse as it learns! You all saw it, it almost fell to my death just now."

Gu Li, who was trying to find boat materials, didn't pay attention to his back. When he heard the movement, he got up and looked at the grinning Dao Porling. After finding no injuries, he said: "These rocks are wet and slippery. It's easy to fall when you come down. You Don't blame Iris for everything."

Dao Porling yelled for injustice, held back his words for a long time, and before he could say anything, he saw Iris's weak face that he only had in front of Gu Li, and suddenly became angry and said: "You just face it!"

Sitting cross-legged on the ground with arms crossed and angry, "If I don't coax me well today, I won't leave."

Gu Lile was stunned. He pulled over two discarded iron doors and kicked off the extra rotary handles on them. "Although there seems to be nothing on the ground, there must be a lot of mutated bacteria." Impressed, he said again: "Speaking of which, I just found a strange thing in this river channel. If I don't have Kirch's more than 30 years of experience as a wizard, I'm afraid it's hard to see what it is. I don't know if it will affect it. Let's go out."

"Don't scare me with new things. This place is hot and humid. There can be something strange." Having said that, Dao Porling still couldn't help looking towards the direction of the river with his chin raised curiously.

The water quality is very clear, and Mimir squatted on the bank, wanting to fetch water with a jug, and suddenly exclaimed: "There is something under the water, it will eat my jug!"

Mimir quickly tightened the strap of the kettle and pulled it ashore, only to see that the bottom of the kettle was filled with a circle of black jelly-like liquid, which was adsorbed to the bottom of the kettle with many thorns.

"What kind of creature is this?!"

Dao Porling rolled his eyes, "What kind of creature, it's called ferrofluid, it doesn't have life and it won't hurt people." He got up and walked to the river to check, and then said to Gu Li who was busy, "Don't be so busy, your The broken door has been oxidized to slag, even with a dozen pieces of pure fluorite, it will not be able to float on this river.”

Just as Daoporing expected, these mechanical doors were indeed scrapped.Not to mention placing fluorite, it is as brittle as a biscuit, and it will break with a little force, and it can't bear people at all.

Gu Li gave up, sighed and said, "You should bring the previous tree trunk with you."

"What is magnetic fluid?" Mimir couldn't help asking.Knowing that it is non-toxic and does not bite people, I even touched the many V structures at the bottom of the kettle.

Dauporin trimmed his beard pretending to be knowledgeable, "Magnetic fluids are insoluble in water, and look a bit like kerosene at first glance. They will flow to places with high magnetic field strength under the action of an external magnetic field."

He walked to Mimir's side, took the kid's water bottle, broke a magnet from the bottom of the bottle that he didn't know when it was attached, and threw it into the water with his hands.

"But it's really strange. How can there be so much ferrofluid in this dark underground river? I've heard of using magnets to purify water, but I haven't seen ferrofluid used to lay the bed of a river."

Gu Li shook his head. Regarding the magnetic fluid, he only saw it once when he was a child, and it was still regarded as a kind of toy when practicing magnetic fields with his brother.What it can be used for specifically, has never been learned in any book or from the mouths of the ancestors.It will appear here, and it may also be related to the experimental body.

"Let's think about how to get out. The slope of this river is not low, and the exit may still be underground."

Mimir was surprised when he heard that, "Didn't you just say that there is a way out underground?"

Gu Li smiled and said, "Are there any better options?"

There is nothing to carry, so if you want to go out along the river, you can only go directly into the water to cross the river.

But fortunately, the depth of this river is only to the waist of an adult, and the water temperature is moderate and not cold.It's just that the sight is blocked by the magnetic fluid, so it creates the illusion of unfathomable depth.

At the end of the river is a cave with a height of two meters. Although you can stand up straight and walk, the distance between the two sides is very narrow.Only one person can pass at a time.

The speed of the water flow is not turbulent, but in order to prevent people from slipping, Gu Li still connected everyone's waist and abdomen with climbing ropes.

The only headache is that the underwater magnetic fluid slows down the speed of walking in the water, and you can't see the bottom, so you can only move forward slowly.

He walked at the front of the line to open the way, while Iris stood guard at the end of the line.

Logically, the two walking in the middle should be the safest, but Mimir, who was in the third place, still couldn't help trembling and panicking.

Human beings will panic about the unknown, or walk in a dark underground river where the bottom cannot be seen. This is simply a double torture both physically and mentally.

In the quiet cave with only the sound of water, Mimir suddenly screamed while holding the rock wall on the right: "Yes, yes, there is something! Under the water, it is biting me!!"

The water splashed, and Mimir, who was already incoherent because of being too panicked, jumped onto Iris, closed his eyes tightly, and dared not open his eyes to see what happened on his feet for a long time.

Gu Li glanced back to check, and saw that Mimir's ankle was wrapped with a broken fishing net, and there were many discarded and damaged plastics hanging in the fishing net.

Dao Porling had the illusion that his soul was going to heaven after being frightened, and he gasped and said, "I'm blind to your dog eyes, let's see for myself what it is."

Mimir looked down at his feet trembling all over, then let go of Iris with a big sigh of relief, tore off the garbage and threw it away, and said with a smile: "I just think everyone is too nervous, I want you to relax."

While talking, Gu Li, who was opening the way ahead, suddenly bent down and picked up a half-remained plastic washbasin and a small amount of daily necessities from the water, and said: "The speed of the water has slowed down, and the slope of the river is not as steep as before. The accumulation of rubbish will only increase in the future, everyone should be careful when leaving."

Although he knew it was a false alarm, his nerves hadn't recovered from the fright just now.Mimir heard the voice coming from the depths of the cave, and tremblingly said again: "You guys, did you hear that?"

Gu Li became vigilant, and turned the light of the ring to the depths of the cave where the sound came from, "It's very regular, like the sound of some large equipment."

Mimir: "It can't be the big spider on the mural..."

Iris, who was walking at the end, untied the rope tied around his waist and abdomen, supported the rock wall and squeezed in front of Gu Li to listen.There are regular sounds of instruments every five seconds, as well as a large number of high-frequency flapping sounds of wings.

"What do you feel?" Gu Li asked.

Iris put his arms around him to protect him, and said, "A lot, flying insects."

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Yu Ling:

Thank you for the fish food that Wu Qiong cutie sent last night!

Magnetic fluid, also known as magnetic liquid, ferrofluid or ferrofluid, is a new type of functional material, which has both the fluidity of liquid and the magnetism of solid magnetic materials.When there is no magnetic field around, the ferrofluid acts like an ordinary liquid; but when the container containing the ferrofluid is placed next to a strong magnetic field, the surface of the ferrofluid will harden, and many spikes will grow, pointing in the direction of the magnetic field lines .This phenomenon is known as Rosenweig instability.

In reality, ferrofluid has many functions, and it is also very helpful in medicine.The specific content will not be elaborated here, and the information comes from Baidu.There are some adaptations in the novel, and there are many places that cannot be studied carefully, so there is no need to study it carefully.