"Sir, I'm starting." Chen Yuan raised the cardboard, and after receiving the approval from the magistrate sitting on top, he put on gloves and a homemade mask.

In the middle of the custom-made iron frame, a white porcelain crucible the size of a porcelain cup was placed, and an alcohol lamp made of purified white wine was placed below.

Pour the yellow iodine solution extracted from kelp into a white porcelain crucible, light the alcohol lamp, and place the rice paper with fingerprints on top of the crucible.

In the eyes of everyone, Chen Yuan is like a fool, holding a piece of white paper and turning it over and over to make fun of others.

After a while, purple gas rose from the white porcelain dry pot.

"Zi Qi, this is an auspicious image!" When Guan Zhixian saw it, his hands were shaking with excitement and he couldn't sit still. This must mean that God is predicting that the little girl's method will work!

"How can yellow water turn into purple gas?" When the government officials saw this, they looked at each other and looked at each other. They didn't understand the reason at all, "Could this be a fairy magic?!"

Regarding everyone's exclamations, Chen Yuan could only say: If you learn physics well, you will not be afraid of traveling through the past and present. If you don't learn physics, life will be full of magic.

In the future, she must give everyone a good chemistry class with Teacher Chen, lead ancient criminal investigators to break feudal superstitions, and use scientific methods to solve cases.

Wei Xian Cheng, who did not dare to criticize him in front of the county magistrate, could only scold the astonished Yamen servants, "What kind of magical method is just an alchemist's deception, and I don't know what kind of tricks Li Fei picked up from reading random books.

By fumigating the purple gas, you can extract fingerprints? Why not just use firewood to smoke the gas black? You waste manpower and material resources with her and ruin so many good things."

Li Fei's broken settlement, the precious kelp must be said to be some kind of kelp.

It was a precious seafood brought back by the merchant from thousands of miles away. He couldn't eat kelp a few times a year, but she took it and burned it to ashes...

Are you angry or not?

What's even more irritating is that the miser, Guan Zhixian, actually lets the mute woman do mischief.

The county government did not have that much budget, so the county magistrate gave all the kelp brought from his hometown to the mute.

By the way, the magistrate not only gave more than ten feet of dried kelp to the mute girl, but also gave a dozen pearls from the magistrate’s wife’s jewelry box to the prodigal mute girl.

Moreover, more than ten fine pearls were all ground into powder by that hateful mute...

Kelp ash, pearl powder... Wei Xian Cheng's heart was broken.

After knowing the news, he was in a restless trance for two days and had nightmares for two nights in a row. He dreamed that all the treasures he had collected were dug out by the mute woman, burned to ashes and hammered to powder in front of him.

.

You are in a pile and I am in a pile, and no one can recognize each other.

At that moment, Wei County Prime Minister truly felt that the poor people in Dumin Village were really wealthy owners in the past, even a mute girl, and those people were probably even more capable of ruining good things in the past.

It's a pity that all the money was confiscated when he was in the capital, and it was impossible for the border officials to take a lick of the soup.

The more he thought about it, the more resentful Wei Xian Cheng became towards Li Fei.

Chen Yuan ignored the interference from the outside world and carefully turned over and over to smoke the paper in his hand.

Iodine is heated and sublimates into purple iodine vapor. The iodine vapor physically adsorbs to the sebum in the fingerprint, and then the iodine reacts with the sebum acid in the fat.

After a while, three brown fingerprints of different sizes appeared on the pure white paper.

"Appeared!"

"It really looks like a fingerprint!"

Many people had been staring at Chen Yuan, but the sharp-eyed people noticed it immediately and started shouting in excitement.

In charge of the county magistrate, Lieutenant Ge County immediately jumped down from his chair and wanted to run over to take a closer look, but was stopped by Zeng Shuisheng and Liu Yanchun.

Doubts appeared on the faces of the two adults, but Wei Xian Cheng, who was sitting motionless on his chair, was the first to attack, "You are so bold that you dare to stop the adults. Have you done anything to deceive us? You are afraid that the truth will be revealed."

, you dare not let the county magistrate come closer to check?"

"No, that's not the case..." Zeng Shuisheng was so frightened that her eyes turned red when Wei Xian Cheng shouted.

Liu Yanchun patted him on the shoulder and signaled him to stop talking, "My lords, the second senior sister is wearing a mask because the purple gas is toxic and smells bad, so she said in advance that before fixing the fingerprints, everyone should

Don't come near."

"Poisonous?" Guan Zhixian took a big step back in fear of his life, and everyone covered their noses with their sleeves.

Wei Xian Cheng did not give up any opportunity to suppress the mute, "Poisonous! Then why did Li Fei only prepare masks for herself and not for us? What is her intention?"

"Adults, don't worry. This kind of poisoning is not that poisoning. It will not kill anyone. Inhaling a large amount will cause uncomfortable runny nose and tears, burning of the throat, coughing, difficulty breathing, and phlegm." Chen Yuan has participated in these precautions in advance.

The person who made the material said that Liu Yanchun remembered it well and had the courage to explain it clearly in front of adults.

Liu Yanchun pointed to Chen Yuan, "If she doesn't wear a mask, it will affect the extraction of fingerprints. We are far away, so it won't be affected at all. Everyone stays where they are and doesn't smell the unpleasant pungent smell. It's okay.

of."

Wei Xian Cheng wanted to say something else, but he saw Chen Yuan scooping a spoonful of white powder into the clay pot marked with starch, and using a small sieve to spread a thin layer of starch evenly on the already visible brown fingerprints.

"Haven't the fingerprints been extracted? What else is she going to do? Why did she sprinkle starch on the paper?"

Chen Yuan had long expected that she would be asked a lot of questions during the experiment. She could not speak or stop the experiment to write answers, so she made preparations in advance.

Worried that Liu Yanchun would not be able to remember so many new terms, he wrote down a piece of paper and wrote down answers to common questions.

Liu Yanchun took out the paper, found the corresponding question, and read out according to the script, "The invisible and colorless fingerprints on the paper will appear as brown fingerprints after being fumigated with iodine vapor. However, iodine will sublime at room temperature, so the iodine fumigated fingerprints will follow the

As time goes by, it will fade and disappear, so starch fixation method must be used to preserve fingerprints for a long time. The basis is that starch will turn blue when exposed to iodine."

As he finished reading, Chen Yuan's side had already wetted the starch sprinkled on the paper with water vapor, and the originally brown fingerprints turned into blue fingerprints in full view of everyone.

One of the yamen servants couldn't help but patted his thigh, "I have a mother-in-law, it's so amazing!"

"The fingerprints that were originally invisible turn brown for a while and blue for a while. How is this done?"

Zeng Chi couldn't hold back his inner excitement at this moment. He covered his nose with his sleeve and approached Chen Yuan, "Now, are you really able to retain your fingerprints permanently?"

Chen Yuan shook his head, and Liu Yanchun found the answer on the paper and answered for her, "It can only be kept for a long time, not forever, so it is best to find an artist to draw it one by one according to the fingerprints and save it."

"This...this is not bad."

Although everyone was puzzled, Zeng Wuzuo said so and nodded in agreement.

"It's so good, but the ink pad doesn't last long." There was a group of people, and Wei Xian Cheng got angry when he saw them, "What's the use of extracting fingerprints on the paper? Will the murderer use paper to kill people? Is there any point in spending so much time doing this?
Chapter completed!