"Master, what exactly is the black pot vegetable you are talking about?" Gu Qing asked.

"That's a kind of sea dish. We saw it in the East China Sea, but it was not available in Chang'an." Sun Simiao said, "There is a kind of medicinal material called Kumbu that can be cured. It is sold in the clinics in Chang'an, and it is also available here. What's the relationship between iodine and big neck disease? Who has big neck disease?"

Gu Qing slapped his forehead and forgot about traditional Chinese medicine. His ancestors' knowledge was indeed profound. "Master, give me some kombu, I'm of great use."

"Who has a big neck disease? Let's go and see it myself. You are a little slutty in your medical skills. What if you get a cure?"

"No one has big neck disease, it's just that I'm useful." Gu Qing walked into Sun Simiao's prescription and searched for it, "Master, where is the Kunbu you are talking about?"

"Go out." Sun Simiao was worried about watching Gu Qing make trouble in his pharmacy and took out a pack of medicinal materials, "This is Kunbu."

After taking Kunbu, Gu Qing smiled and accepted it, "Thank you, Master. It's really easy to find a place without any effort. The camera can be used."

Sun Simiao fell into thinking about what the camera was.

Back in his laboratory, Gu Qing became busy again, burning kumbu into ashes and soaking it in water, and starting to try to extract iodine. He was not afraid of having knowledge around the world. The teacher taught him well and reading could finally come in handy.

Next, put this silver-plated copper plate in the iodine solution to make silver iodide.

After making everything, Gu Qing excitedly put it in the dark box and began to experiment with imaging, starting with the scenery.

Li Zhi looked at him strangely, "Just leave this secret box?"

"Yes!" Gu Qing nodded, "Will you give His Highness the King of Jin a surprise, the mystery of knowledge and the greatness of science."

"Science? It's science again." Li Zhi was operating something in secret, "Can I see it?"

"Look." Gu Qing pulled Li Zhi into the half-man-high secret box.

Entering the dark dark box, Li Zhi saw a small hole, and the light and shadows shone on the silver-plated copper plate. He said in surprise, "Gu Qing, why is this inverted?"

"It's indeed an upside down, it's because of the light." Gu Qing explained, "It should be fine. Your Highness, please let me go."

"alright."

Gu Qing closed the lid of the small hole, pushed the secret box back home and began to wash the photos.

Li Zhi was standing outside the laboratory. Gu Qing closed the doors and windows. What was a shameful secret? After hesitation, he walked into the room.

Seeing Li Zhi come in, Gu Qing hurriedly said, "Your Highness King Jin please close the door."

Carefully closing the door, Li Zhi watched Gu Qing wash things, "What are you doing when washing this board?"

"This water is dissolved with salt." Gu Qing said, "There is something in the salt called sodium chloride, which can help fix the film."

"What is fixing?" Li Zhi was puzzled again.

"It's the shadow, the shadow shining on this board." Gu Qing explained with a smile, "Just let His Highness King Jin see it, and the reflections of the scenery are reflected on this board through small holes, right?"

Li Zhi tried harder.

"That's right." Gu Qing continued, "We have to leave the shadows of those trees on the board, but unfortunately there is no film, so it's much easier if it's done."

"What is film?" Li Zhi asked again.

"This is a long story, and it is difficult to explain it to His Highness King Jin." Gu Qing said calmly, washing the washed bottom plate and then drying it.

After everything was finished, Li Zhi looked at the silver board for a long time and couldn't speak. He came to the place where Gu Qing was imaging like a devil. The trees, flowers and plants were exactly the same, and even people in the distance were there.

"How is it? Isn't it very magical?" Gu Qing said as he looked at Li Zhi's expression.

"This is also magic?"

"This is not magic, this is called science." Gu Qing put away the silver board and greeted Fan Jian, "Call the house and let's take photos together."

"Okay." Fan Jian also smiled and nodded.

The family sat in front of the house with a row of chairs in a row. Sun Simiao spoke in a twist, "Just just stand by, Gu Qing, you sit in the middle."

"Master, just sit in the middle." Gu Qing said with a smile.

Yang Sheng and Di Renjie also came, and they couldn't figure out what Gu Qing was doing.

"You stand here." Gu Qing directed the seats.

Sun Simiao sat in the middle with two children in his arms. Gu Qing said to Fan Jian, "Remember to remember to wait as the image above stops shaking, then cover the lid immediately."

"I understand." Fan Jian nodded vigorously.

Gu Qing sat next to Sun Simiao, Wu Mei sat next to him, and Yang Sheng, Di Renjie, Li Zhi and Xiao Yizi on the other side.

After sitting for about ten minutes, Fan Jian covered the lid and said, "Master, is this enough?"

"Let's take a look." Gu Qing walked into the dark box and looked at the bottom plate. The family only had the upper body printed on the board, and everyone's expression was clearly inside. Sun Simiao's surprise, Wu Mei's curiosity, Yang Sheng's laziness, and Di Renjie's thoughts.

Holding the bottom plate, Gu Qing came to his laboratory again to start fixing.

"What is the teacher doing?" Di Renjie said curiously.

"This is called taking photos." Li Zhi looked up and said to Di Renjie, "You don't know about taking photos. I told you that Gu Qing only taught me this time, haha!"

Di Renjie walked into the secret box and took a look at the situation inside, then looked at one of the small holes, "The mystery should be in this small hole."

"That's right!" Li Zhi said proudly, "This is called optical imaging. Do you know optical imaging?"

"Do Your Highness the King of Jin know?" Di Renjie asked back.

"I..." Li Zhi said for a moment, "I want to know, Gu Qing didn't tell me."

"Oh, so that's it." Di Renjie nodded in a clear understanding, "It turns out that His Highness King Jin doesn't understand either."

"I will understand sooner or later." Li Zhi said dissatisfied.

After the image on the board was clear, Gu Qing framed the base plate, like a frame, carefully hanging it in the lobby of his home.

Sun Simiao was frightened when he saw his own bottom plate. Everyone was clearly visible on the bottom plate as big as a table, and his facial features seemed to be frozen.

"This..." Sun Simiao was so scared that he couldn't speak, "Is this myself?"

"Well! It's the master." Gu Qing said proudly, "How about it, your disciple is very capable."
Chapter completed!