Seeking Truth with a Sword

"What?!"

Di Wu hadn't heard Li Ang clearly and shouted with his head down.

Li Ang shouted loudly, "All the jet holes are paired in twos! Find a way to grab the openwork metal plates above the holes on both sides, toggle them alternately, and repeat several times. This might stop the Gang Wind from surging!"

"How can you..."

Di Wu's voice was drowned out by the wind. He glanced at the people who were struggling, gritted his teeth, held up his shield, moved forward, and came next to Zhu Yuyin.

Following Li Ang's instructions, he squatted down, opened the closed openwork metal plate, and pulled down another metal plate beside it.

As before, with the pulling of the second metal plate, accompanied by a rolling sound, the wind first weakened and then strengthened.

After repeating this more than ten times, something in the space behind the metal plates suddenly broke, and the holes corresponding to the two metal plates no longer emitted Gang Wind.

Effective!

Di Wu stared in astonishment, waved to the other people on the ground, and everyone crawled forward, continuing to close the second, third, and fourth group of Gang Qi channels.

Roughly twenty-two minutes later, the Gang Qi channels close to the ground were all closed, and the Gang Wind vortex lingering in the hall had also weakened significantly. Only beneath the dome did some remnants of the Gang Qi vortex remain.

The people, who had escaped death, removed their Zhang Island Ghost Rong respirators that had depleted their gas, lying on the ground panting heavily.

Di Wu, whose face and body were covered in wounds, approached Li Ang, bowed slightly, and said respectfully, "Mr. Li, how did you..."

"How did you know that toggling the openwork metal plates back and forth would close the Gang Qi channels?" Zhu Yuyin, also lightly wounded, stepped forward and asked directly.

Li Ang glanced at him and did not answer directly, but slowly said, "Have you ever navigated a large ship on a river?"

Zhu Yuyin was taken aback. "What?"

"If you have extensive experience navigating ships, you should know that two ships should not sail too close to each other in parallel, either in still or flowing water. Once this happens, the two ships will uncontrollably approach each other and collide. If two ships are one behind the other, sailing closely, the situation can be even more dangerous. The rear ship will be pushed by the water flow and collide with the front ship."

Li Ang spoke casually. In water or air flows, if the speed is low, the pressure is high; if the speed is high, the pressure is low—this is the basic theory in fluid dynamics, Bernoulli's principle. If two balloons are hung on a rope, close to each other but at a distance, and air is blown towards the middle, because the speed of the airflow in the middle is high and the pressure is low, the two balloons will move towards each other and collide. In the memories from Otherworld, the yellow warning lines on high-speed train platforms followed the same principle—if one gets close to a high-speed moving train, the sudden decrease in air pressure will "push" one toward the train, causing accidents.

"The principle of these holes is essentially the same. Look closely at the holes on the wall. They are all paired in twos, each with an openwork metal plate above. When one metal plate closes, accompanied by a rumbling sound from within the mountain wall, the wind first weakens and then strengthens. The nearby hole no longer emits wind."

Li Ang casually explained, "The wind changes after the rumbling sound. I deduced that each of the two adjacent holes has its own intake passage. The two passages meet in a chamber and lead to the source of the Gang Wind."

Li Ang casually drew a diagram on the ground resembling an upright stem with a short, perpendicular bar on top, and said, "In the recess of the chamber, there is a spherical object—likely a sturdy stone or iron ball. This object is located in the recess of the chamber and usually does not move. When the left openwork metal plate is closed, the airflow in the chamber will preferentially surge out from the hole on the right. The airflow on the right side of the chamber then accelerates, generating a force. This force is as if it 'sucks' up the stone ball, causing it to roll and block the airflow passage to the right hole.

At that time, the airflow from the hole on the left had weakened due to obstruction—this was the initially windless period.

But soon, the airflow continued to enter the chamber unabated. Since the hole on the right was already blocked by the stone ball, the remaining air could only rush out through the hole on the left. This resulted in an increasing flow of Gang Qi from the left hole.

Simply put, the stone ball in the chamber acted as a direction selector. Whichever side was blocked, the airflow on that side would intensify. What I had Di Wu do was actually to make the stone ball roll back and forth in the chamber, using Gang Qi to damage the stone ball, while blocking the air passages on both sides, thus reducing the airflow from both."

Di Wu and the others felt as though they had understood, yet hadn't quite grasped it.

Li Ang glanced at Zhu Yuyin and said, "Of course, your method of changing the pattern positions according to the sixty-four hexagrams might also work. In any case, as long as we can survive, that's enough. However, the stone balls in each chamber could potentially shatter further at any time, causing Gang Wind to regenerate. It's best to take action as soon as possible."

Hearing Li Ang's words, Jiao Cheng pressed his lips tightly and stood up from the ground.

The Dragon-breaking Stone at the entrance of the passage was indestructible. Several tattooed strongmen and two Sword Cultivators had tried to chisel it open, but the time it would take was unknown. The Melt Soil Talismans they brought were also slow to take effect.

After pondering for a moment, Jiao Cheng left five people on site to continue using the Melt Soil Talismans to melt the rock layers surrounding the Dragon-breaking Stone, determined to find an exit before the Gang Wind regenerated.

The rest headed to the center of the hall and discovered a bronze door embedded in a rotatable ring.

After prying open the bronze door, however, they didn't find stairs leading downward, but instead a viscous, pitch-black liquid emitting a pungent odor.

"Is this...shizhi?"

Jiao Cheng was utterly astonished and took a bamboo pole handed over by his subordinate, stirring it into the shizhi, which was actually a layer of petroleum.

The petroleum was viscous, with no exit or hidden compartments. Beneath the bronze door was really just a pool of petroleum.

"Where is the path?"

Jiao Cheng clenched his fists and scanned his surroundings.

The only barriers in the cavernous hall were the mountain walls. From the poetic inscriptions of sword marks on the dome, it was undoubtedly the work of the Banished Immortal. But where was the crucial path?

Jiao Cheng had his subordinates carefully search for any traces around, trying to push the ring around the bronze door, but doing so only caused the petroleum pool to rotate.

"Could it be that we need to ignite the shizhi in the pool?" Jiao Cheng muttered to himself, still unable to make up his mind. Petroleum was flammable and hard to extinguish. Recklessly setting it alight could lead to unforeseen consequences.

"..."

Li Ang looked up at the dome and suddenly said, "Is that amber above the dome?"

"Hmm?"

Jiao Cheng and the others followed Li Ang's gaze upward, seeing a faint brown-yellow glow above the bronze door, resembling a cluster of amber encapsulating the long shadows of iron chains.

"If the path is above the dome, should we ignite the Shizhi Pool to melt the amber above?"

Li Ang estimated the distance to the dome and the impact of the upper Gang Wind, suddenly realizing the function of the rotatable ring around the petroleum pool, and murmured, "So that's it..."