Chapter 682: Measuring Experimental Data

He had experimented many times in Panlong City, and even calculating backward from the stars proved very accurate. As Xu Shichu had mentioned, this formula could not only determine the trajectory of the Celestial Net Star but also encompassed all nine stars of the Big Dipper.

But tonight, with no stars or moon, the night sky was like a blank canvas, severely testing He Lingchuan's abilities.

Of course, he dared not complain. Who could guarantee clear, star-filled skies on the actual day of the operation? What if it was cloudy, just like tonight?

Zuju glanced at him. Despite being a fire monster, his tone was icy: "Can you even do this?"

"Whether I can or not isn't up to you to decide," He Lingchuan shushed him. "Don't make noise; I'm not good at mental calculations to begin with."

If only Master Sun were here.

"Fly back five zhang, yes, that's right, then descend. It should be right here!"

As the three watched, the small bat in the air suddenly spun, then involuntarily flew sideways, gliding over ten zhang away.

"Hmm?" Dong Rui controlled it, steadying its flight, making it circle back and fly towards the spot again.

Once again, the small bat was pushed away by an unknown force.

It quickly flew down, returning to its master's side.

After communicating with it, Dong Rui told He Lingchuan, "There seems to be turbulence there. Birds get swept away as soon as they approach."

Air currents often appear at high altitudes, which birds use for flight.

"Could it be there?" He Lingchuan pondered. "Let's try from a different direction."

This time, the small bat flew from the west. Sure enough, upon approaching the area, it was again swept away by the air currents.

"This air current is fifteen zhang (over forty meters) above the peak, but its horizontal diameter is at least several tens of zhang. Is this logical?"

Zuju mused, "The core of the Spirit Gathering Formation also has a whirlwind array attached to it? Why wasn't this mentioned in your intelligence?"

According to the memory of Zaifu Kua, the Vice Minister of Works, there was no whirlwind array outside the formation's core. "Perhaps the Heavenly Palace added it later?"

"It pushes away irrelevant objects; otherwise, it would be awkward if birds flew into it directly, and it would also reveal the core's location," He Lingchuan exhaled. "Birds often encounter air currents, so they probably wouldn't find it strange. Besides, the core frequently moves and might not be here tomorrow. Of course, these are just conjectures; it's best to confirm them."

"How do we confirm it?" Zuju tilted his head. "Should I throw a few large fireballs up there to test?"

"No!" Its attacks were always full of sound and light effects. He Lingchuan quickly stopped him. "Are you trying to tell everyone we're hiding here?"

"You can just lie low," he retorted. As a local mountain and marsh spirit, what was wrong with shooting off a few fireworks into the sky? Was it not allowed?

Seeing Zuju eager to try, Dong Rui couldn't help but say, "If you hit it, the Heavenly Palace will know. How will we launch a surprise attack then?"

The fact that the core of the Spirit Gathering Formation was not hidden in the void was a taboo for the Heavenly Palace. Regardless of how Zuju knew this, it would almost certainly alert them.

"This mission is already difficult; can we not add more complications right now?"

Zuju, who had already conjured a fireball, extinguished it with a soft pop upon hearing this. "Then what do you suggest we do?"

It turned out this fellow was merely cunning, not truly intelligent. He Lingchuan understood, and immediately asked, "You've presided over Mount Xu for over four thousand years. Can you influence the weather here?"

"Psh," he scoffed. Any ordinary mountain and marsh spirit could do it, and Mount Xu was his very body. He could conjure wind and rain here at will. "A piece of cake."

"Then summon a hailstorm, the finer the ice shards, the better."

Dong Rui subtly gave him a thumbs-up. The monster's essence was rock fire; it should detest rain, yet He Lingchuan was asking it to conjure hail.

To their surprise, Zuju showed no resistance. "No problem. It just rained tonight, anyway." And it was cold.

Volcanic eruptions often cause hail and heavy rain. Besides, was a several-thousand-year-old grand demon afraid of a little rain?

He Lingchuan heard Zuju's entire body crackle.

This type of demon didn't use its mouth to chant spells. Instead, its rocky body segments collided, producing specific frequencies of clacking sounds. They weren't melodious but had a percussive rhythm.

These collisions also caused the peak to vibrate slightly, akin to a magnitude three or four earthquake.

Naturally, Zuju also knew not to create too much commotion to avoid alerting the Heavenly Palace, so the earthquake's range was limited to this low peak.

Then, like a human, he bowed forward towards the sky, extending both arms with palms upward, cupping a handful of grit in each.

With a whoosh, a strong wind swept through, and the grit in his hands vanished instantly.

The wind was so powerful it almost swept people into the sky. The guards on Tianji Peak quickly sought shelter in the hollow of the Questioning Tree.

After about ten breaths, the strong wind ceased, and small, hard objects began to fall from the sky, rattling against the rocks and wood.

He Lingchuan felt a few strikes on his face too. Reaching out, he touched small, cool, hard ice shards that melted upon contact with his body heat.

The hail had arrived.

According to Zuju, summoning strong winds and heavy rain was simple, and egg-sized hail was even easier. The most challenging part was continuously conjuring these tiny ice shards, barely larger than raindrops, as their size was difficult to control.

Too much force could easily activate the core's attached defensive array.

He Lingchuan and Dong Rui looked up at the sky. "Do you see anything unusual?"

"No."

A quarter of an hour later, the hail stopped.

Dong Rui quickly seized the moment, intending to send the bat demon puppet back into the sky.

Zuju, however, shook his head. "No need. The volcanic grit I sent up with the strong winds is currently suspended motionless right in the center of the turbulence. I can feel it!"

He had mixed tiny grit into the hail and dropped it towards the turbulence. As it was essentially a small part of his body, he knew exactly where it landed.

This was the advantage of being a local master, something others could only envy.

He Lingchuan couldn't help but snap his fingers. "Excellent! My calculations were correct; the core is indeed there!"

Accurately calculating the core's location meant their mission was a quarter successful—a remarkable breakthrough!

"The defensive array didn't activate either." Otherwise, the grit wouldn't have landed inside the core. This confirmed their earlier assumption: objects too small or light would not be deemed an attack by the defensive array.

Although the core was protected by turbulence, the wind blew in all directions. Such tiny grit might not be completely blown away; after spinning a few times and colliding with the hail, there was a small chance it could penetrate the turbulence and fall into the core.

"But there's turbulence around the core. How do you approach it?" Dong Rui questioned. "Is there a way to pass through it?"

He Lingchuan rubbed his hands. "We might need a wind-repelling artifact."

One problem arises, one problem gets solved. This was the purpose of the test flight.

Zuju immediately said, "A trivial matter. I have a Wind-Stillness Pearl here, obtained two thousand seven hundred years ago from slaying a sorcerer. Nourished by my spiritual energy, it has never failed."

He Lingchuan gladly took it. The pearl was only the size of a quail egg, with fine spots on its surface, not as lustrous as a regular pearl.

Upon holding the pearl, the wind around him indeed became very weak.

"You'll need to time its use carefully," Zuju reminded him. "You can't wear it constantly, or the bat you're riding won't be able to take flight."

Of course, for a Wind-Stillness Pearl, how could winged creatures fly without wind?

"Only one?" He Lingchuan was not satisfied. "We'll need at least two."

Zuju was speechless, wishing he could just swat He Lingchuan dead. "Do you think this is a cultured pearl, readily available when you cut it open? The Wind-Stillness Pearl in your hand could fetch at least ten thousand silver taels at auction."

He Lingchuan chuckled. Ten thousand taels for a Wind-Stillness Pearl? This fellow really had the nerve to say that. Unless it had a special purpose, who would be foolish enough to spend that much?

"One is indeed not enough," he said seriously. "This is purely a technical discussion."

Zuju impatiently retorted, "Then scrape some powder off the pearl and make do with it!"

"...That works too?" And he said it wasn't a pearl?

"I've tried it, but the scraped Wind-Stillness Pearl powder only lasts for two hours."

He Lingchuan breathed a sigh of relief. "That's enough."

Powder form was better and lighter. But how idle must this old thing have been to think of scraping powder from a Wind-Stillness Pearl?

"We still need to test the radius of the turbulence." After all, once up there, he wouldn't be able to see anything. If he timed the use of the Wind-Stillness Pearl incorrectly, he and the bat would crash directly into the defensive array.

"Leave that to me," Zuju said confidently. "I'll play with it."

As the local mountain and marsh spirit, he had plenty of time and energy to proceed by trial and error.

Since Zuju had taken on this task, Dong Rui sent the small bat back into the sky to measure the actual size of the core by approaching it from different directions. Of course, this couldn't be done too frequently to avoid detection.

The demon puppet ascended more than a dozen times, taking over two hours in total.

"This thing is circular," He Lingchuan concluded after numerous tests. "Including the surrounding air currents, its diameter is about thirty zhang."

Zuju's task, then, was to measure the "thickness" of the air currents, so He Lingchuan could precisely time the activation of the Wind-Stillness Pearl.

After noting down the data, the two descended the mountain.

This time, Zuju led them along a different route, departing through a hidden valley.

This was an underground waterway formed by years of stream erosion. Later, the stream changed its course, and this became a hidden underground valley, completely invisible when viewed from the mountaintop.

Upon reaching this spot, Zuju suddenly stopped. "The grit has been cleared away."

He Lingchuan had been silently calculating the time. "About two 'ke' (specifically, 33 minutes)," he said.

"The grit was too fine, so it likely wasn't manually cleared," He Lingchuan said, smiling. "It was probably activated by a cleaning array. It seems this array isn't very diligent, either." The interval between each activation was quite long.

How many arrays had the Celestials layered onto the core later? Old official Zaifu Kua's memory contained none of these chaotic arrays.

He Lingchuan suddenly remembered something and turned to Zuju to ask, "By the way, has there been any unusual activity at the Stargazing Tower these past few days?"

"No, it's been business as usual." Zuju, with his own hidden agenda, naturally paid extra attention to the Heavenly Palace.

"Has anyone unusual come up?"

This time, Zuju thought for a moment before saying, "Oh, yes, the Imperial Advisor Qingyang came up the mountain this morning."