Chapter 30

Tingting rushed into the grand hall, heading straight for the wall where the 'ghostly shadow' appeared. Unlike when he first entered, feeling his scalp tingle and his body go numb, this time he was more composed, his mind filled with curiosity.

The image on the wall still existed, as if projected by a projector. However, it was different from what he had seen earlier. Although the palaces were still standing, there were no figures in front of them.

"Ha ha ha, it's just as I thought!" Seeing this scene, Zhao Chen's heart immediately relaxed. He stood in front of the wall reflecting the Eastern Palace, looking up and couldn't stop laughing.

After laughing enough, he lifted the hem of his robe and quickly ran out of the hall. At the entrance, he suddenly pointed at a nearby guard and immediately ordered him to stand in front of the Eastern Palace. He wanted to further verify this fact.

The guard, whom Zhao Chen pointed at, hesitated for a moment, looking at Emperor Li Er not far away. Seeing the emperor nod slightly, he walked towards the Eastern Palace without hesitation.

Seeing the guard stand in front of the Eastern Palace, Zhao Chen immediately turned around and entered the hall again.

He quickly came to the wall and, as expected, saw a faint figure appear in front of the palace, which had been empty just a moment ago. Upon closer inspection, it was clear that this new figure was the guard.

Now that he had confirmed it without a doubt, Zhao Chen felt extremely relieved. It was just a pinhole image, a rare natural phenomenon where light passes through a small hole and projects an inverted image on a wall. This experiment is something that primary school students do in later generations, and the Mohists had already conducted such experiments thousands of years ago, although they focused on the formation of shadows rather than images. The principle, however, is the same.

Modern cameras and photography are based on the principle of pinhole imaging. Damn, just a pinhole image, and it almost scared the living daylights out of me. What a disgrace!

Having thoroughly understood the truth, Zhao Chen immediately turned to leave the hall. Li Er and others were still anxiously waiting outside, and he needed to reassure them quickly.

"Ah!" A sigh suddenly came from behind him. Zhao Chen turned around in fear but found the hall empty. He had clearly heard a sigh, but perhaps it was just an illusion?

He looked around again, finding no one, and shook his head in confusion, walking out of the hall. This time, he paid close attention to any sounds behind him but heard nothing more.

Li Er stood at a distance, his eyes fixed on the entrance of the hall. Compared to before, his expression was less gloomy.

He had seen Zhao Chen's reaction and, especially when he heard Zhao Chen's loud laugh from inside the hall, knew that the young man had found a way to dispel the ghostly shadow.

The ghostly shadow had appeared in the hall for four or five days, causing a stir in the palace. People were privately speculating that it was the spirit of Jiancheng causing trouble.

He had already ordered the execution of those spreading rumors, but as long as the ghostly shadow in the hall remained unexplained, the rumors would continue to spread, eventually becoming common knowledge!

Empress Changsun, standing beside Li Er, looked at the hall entrance with earnest eyes. She had been sad earlier, seeing Li Er's dejected departure, and a tear still lingered on her face.

Seeing the tear, Li Er smiled gently and wiped it away with his thumb. The couple then smiled at each other and looked at the hall with mutual understanding.

At this moment, Zhao Chen's figure appeared from the hall, and from a distance, he called out to Li Er, "Your Majesty, I have figured out what's happening. This phenomenon is quite rare. Don't you want to come and see it?"

Empress Changsun, who had just felt a sense of relief at Zhao Chen's success, immediately turned cold upon hearing his words, her phoenix eyes flashing with anger.

Knowing the hall was dangerous and still suggesting the emperor enter, such a heart is truly despicable!

However, Li Er, upon hearing Zhao Chen's words, frowned slightly and then burst into a powerful laugh, "If it's a rare phenomenon, how can I miss it!"

As he spoke, Li Er walked towards the hall, and Changsun, startled, grabbed his hand. However, Li Er held her hand tightly and whispered something in her ear, causing her frown to smooth out. The couple then walked hand in hand towards the hall.

Li Chunfeng, with a complex expression, watched Zhao Chen from a distance, then let out a bitter laugh and followed the emperor and empress into the hall. He was also very curious about the ghostly shadow.

The group marched towards the hall, with Zhao Chen leading the way. Although he had already explained that it was a rare natural phenomenon and not a ghost, he knew that only by seeing it themselves could Li Er and the others be truly convinced.

As they entered the hall, just like Zhao Chen had experienced earlier, everyone felt their scalps tingle and their bodies go numb. Li Er held Changsun's hand tightly, and although his face showed no emotion, his tightly clenched fist revealed his tension.

Finally, they reached the wall. When they saw the 'ghostly shadow,' everyone's faces turned pale, and the more timid among them began to tremble. Changsun, her face pale, leaned against Li Er.

Without delay, Zhao Chen immediately ordered the guard in front of the Eastern Palace to leave. As soon as the guard left, the inverted figure on the wall disappeared, much to everyone's surprise.

Li Er's eyes lit up as he watched the wall, finding it interesting. He then ordered several more guards to stand in front of the Eastern Palace. As soon as the guards arrived, several inverted figures appeared on the wall.

"Fascinating! Indeed a rare phenomenon!" Li Er repeated the process several times until he was convinced that it was just a projection. He then laughed heartily in the hall, marveling at the phenomenon.

Hearing Li Er's laughter, Zhao Chen decided to take the opportunity to explain the principle of pinhole imaging. Seeing that Li Er and the others were confused, he called for a large curtain to be hung on the opposite wall. The small hole on the wall was temporarily hidden, and time was of the essence; they needed to understand the truth before sunset.

The large curtain was hung on the opposite wall, and the image on the wall disappeared. Zhao Chen then had the curtain removed, and the image reappeared on the wall.

Now, it was clear. The culprit was a small hole in the wall!

Changsun stood straight, her face dark, while Li Er felt relieved, his gloom from the past few days lifting as he laughed heartily.

Zhao Chen took this opportunity to explain the principle of pinhole imaging to Li Er. Seeing that Li Er and the others were still confused, he called for some paper to conduct a pinhole imaging experiment on the spot.

Such a rare opportunity should not be wasted; it would be a sin to let it pass!

By now, the sun had set, and the image on the wall had disappeared. Several oil lamps had been lit in the hall.

Everyone remained in the hall to watch Zhao Chen's experiment. Li Er and Changsun sat side by side on a soft couch, watching Zhao Chen set up the experiment.

Conducting a pinhole imaging experiment was not difficult; Zhao Chen had done it in primary school.

It was simple: find a piece of hard paper about one centimeter thick, poke a hole about three millimeters in diameter, stand the paper upright, light a candle, and bring the candle close to the hole. An inverted image of the candle would appear on the wall opposite the hole.

A simple experiment, nothing more!

Without suitable hard paper, Zhao Chen had to stack several sheets of rice paper, carefully sticking them together, and then poke a hole in the center. Two attendants held the paper at opposite corners, standing a distance from the wall.

Smiling at Li Er and Changsun, Zhao Chen confidently held an oil lamp and approached the paper.

For the first time in the history of the Tang Dynasty, a scientific experiment was about to take place. Li Er and Changsun watched the wall intently, eagerly awaiting the miracle.

Not only Li Er and Changsun, but Li Chunfeng and everyone else in the hall held their breath, their eyes fixed on the wall.

Zhao Chen carefully approached the paper, aligning the oil lamp with the small hole. In the next moment, a flicker of light appeared on the dark wall, and an inverted flame appeared.

The flame flickered with Zhao Chen's breathing, and Li Er's expression became excited, his fingers tapping on his thigh.

Seeing this, Li Chunfeng suddenly looked up and laughed, "Ha," and without waiting for Li Er to speak, quietly left the hall, his back looking desolate.

From now on, the position of the Astronomical Bureau would likely lose its importance in the emperor's eyes!