Chu Tianyi also felt more and more strange as he walked, the passage on this side of the fault zone was simply different from the previous one, and he couldn't imagine for a while why there was such a big difference between the two.

Mu Feng raised the flashlight and found that there were many cracks on the stone walls on both sides, the width was more than ten centimeters, and the narrow one was only about one centimeter. In addition to this, there are some circular holes.

The bearded man looked at these speculations and said, "Is this the kind of trace left after the chisel you said earlier?" ”

"These round holes are, but this crack is not." Mu Feng found a relatively low crack and shone it with a flashlight, "This is quite deep, I can't see the bottom." ”

"These round holes are not deep," Xiao Meng also leaned on a hole to take a picture inside, "It's about a little more than a palm." ”

Chu Tianyi discovered a strange phenomenon, some circular holes cracked, forming a crack, and he couldn't help frowning, "It seems that there are holes dug out by someone here first, and then these cracks." ”

Xiao Meng smiled, "Shouldn't those people chisel the mountain?" ”

"No," Mu Feng shook his head, "This means that after the man-made chiseling here, there have been geological changes, such as earthquakes. ”

"Forget it, don't look at it. It's all a guess, and there's no conclusion. The bearded man urged, "There are traces of these man-made chiselings, at least it shows that we are in the right direction." Let's get out of here. ”

Xiao Meng walked a few steps, still complaining, "I don't understand, since the people have carried out construction and repair here, why not level the ground, it's too difficult to walk." ”

Chu Tianyi looked left and right, "I was also thinking about this just now, I think the height here is enough, and there are still these traces of excavation on the stone wall, is it possible, people back then did not walk on the road, but built something similar to a plank road on both sides?" ”

"Why?" Xiao Meng stepped on the ground under his feet hard, "There's no problem down here, huh?" ”

The bearded man looked at the stone wall, "The plank road shouldn't be, if so, how can it leave no traces at all?" The plank path on the cliff in the canyon still exists, and it won't decay faster than the outside, and even if it does, it will have to leave some residue. ”

"Because it burned." Mu Feng said on the side, and then pointed to a black spot on the stone wall, "Here are the traces of being burned, and I also found some ashes in some holes just now." ”

"Burned?" Xiao Meng was even more confused, "It's pointless to burn the plank road here!" Is it because you are afraid that people will step on the plank road to enter? Besides, you don't need a plank road to enter from here. ”

Mu Feng looked down as he walked, and suddenly he squatted down, not knowing what he was looking at. Chu Tianyi and the others looked around, and saw Mu Feng pinching some tiny red crystals from the ground.

Xiao Meng took a closer look, "What kind of gem is this?" ”

"This is not a gem," Mu Feng smiled, "This is mercury sulfide, and the molecular formula of cinnabar is the same." ”

"Mercury sulfide?" Chu Tianyi also reached out and pinched a little in his hand, "Why is there mercury sulfide here?" Is there a cinnabar mine here? ”

"No," Mu Feng flicked the ash on his hand, "this is not natural cinnabar ore, this is an acquired mercury sulfide crystal." ”

"Acquired mercury sulfide crystals?" Chu Tianyi couldn't help but think for a while, and suddenly raised his head, "You just said that the plank road here was burned, which means that there was a fire here, can you say ......" Chu Tianyi didn't say any more, but looked at Mu Feng in disbelief.

Mu Feng looked at Chu Tianyi with a smile, "I know you think it's incredible, and I didn't expect it, but it seems that this is indeed the case at the moment." Right here," he said, gesturing to the passage where he was, "it must have been filled with a lot of mercury. That's why plank roads will be built on both sides. ”

Xiao Meng, who was confused in the audience, finally couldn't help it, "Can you say it more plainly?" ”

Mu Feng thought for a moment, then pointed at Chu Tianyi, "You can explain." ”

Chu Tianyi was stunned for a moment, scratched his head and sorted out his words, and said: "Assuming that our current inference is correct, mercury was indeed poured here back then, and later the high temperature generated by the ignition of the plank road turned mercury into mercury oxide vapor. Changbai Mountain, where we are located, is a volcano, which contains a lot of free sulfur, and sulfur can react with mercury oxide vapor to form red mercury sulfide, which is the red crystals that Mu Feng found just now. It is precisely because of the discovery that mercury sulfide is formed through the acquired reaction that it proves our inference that there was indeed mercury here and that there was a fire. ”

Xiao Meng looked at Chu Tianyi blankly, and then at Mu Feng, his expression was very helpless. The bearded man next to him had upgraded from a confused head to a head of rain, and he was also stunned for a moment before he nodded and said, "What you said seems to be called a chemical reaction, right?" ”

Mu Feng smiled and shook his head, Chu Tianyi didn't know how to answer, so he gave a thumbs up, "You're right!" ”

Xiao Meng shook his head vigorously, "Okay, I don't understand what you said, but there is one thing we still don't understand, why is there so much mercury here?" Will you be able to refine mercury at that time? ”

"Of course," Mu Feng nodded, "a large amount of cinnabar ore was discovered as early as the end of the Zhou Dynasty, and the ancients also mastered the technology of refining mercury at that time. According to scientists, more than 100 tons of mercury were used in the tomb of Qin Shi Huang. ”

"A hundred tons??" Xiao Meng's eyes widened, "What does he want so many of these things for?" ”

Mu Feng raised the flashlight and shone it forward, and said casually: "In addition to being used to build the rivers, seas and lakes in the mausoleum, it is also used to prevent theft." Large amounts of mercury surround the Mausoleum of Qin Shi Huang, producing a large amount of highly toxic mercury vapor that has deterred tomb robbers for thousands of years. Fortunately, we have the crack in the mountain here that allows the air to circulate, otherwise we would have been poisoned by the mercury vapor from the combustion here. Therefore, mercury can also be an effective barrier. ”

"Barrier?" Mu Feng's words seemed to remind Chu Tianyi, "Could it be that mercury is also infused here for the purpose of some kind of barrier?" ”

Mu Feng shrugged, "I don't know about this!" ”

The "head of rain" next to him finally spoke, "It doesn't matter if he put mercury or a kettle here back then, let's go quickly." How do you make it look like class? So saying, he took the lead and walked forward.

A few people followed the bearded man and walked forward for a distance, and Chu Tianyi suddenly heard the sound of rustling from before, and it seemed that something was still following them. He looked back suddenly, but he didn't want Xiao Meng to look back at the same time, the two of them looked at each other, and said in unison, "You also heard?" ”