Ding Xuewei's question was undoubtedly correct, and the old man's answer seemed to be answered, but in fact he did not give exact information.

"Starting from the capital of our country, whether it is to the east or west, it will eventually return to the original point." Ding Xue put down the pliers slightly, picked out a piece of charcoal and drew a circle on the ground.

"When I was younger, my grandfather said that the world we live in is the center of the sun, moon and stars. At that time, my grandmother said that the world was round, and that we were only on a planet around the sun. She didn't force the two to believe it, she just kept drawing back and forth.

Stop, a sketch of the solar system is presented.

The world in the book is set based on the real world, and naturally, the sun, moon and stars and their entire cosmology are all replicated.

"You may have been to many, many places, but you haven't fully set foot in every corner of our world. Yang Lao, you may think this is ridiculous, but there are many things that a child like me can imagine, and it is not something that a person like you who has not fully set foot in every corner of the world can insist. ”

If the theory that the earth is round makes people laugh, then the solar system map makes people have to think.

Ding Xuewei is smart, but her intelligence does not match the age of the environment she is in.

Not to mention that the world revolves around the sun, even artificial incubation, pollination and other ideas cannot appear in her mind.

"Then tell me what kind of fuel can make the flame temperature high enough to melt this material." The old man put away his sharpness and returned to his previous kindness.

Ding Xuewei knows very well that she can't express herself at this time.

"With coal or gas."

“··· Gas. The old man raised his eyebrows.

He can be sure that he does not know at all what coal is, this gas, as it sounds, is clear, but can not imagine.

The stove was too hot, Ding Xue glanced at it and pointed not far away.

There was not only the recliner that Fang Heng had sat on before, but also a small square table and two wooden stools, on which a set of tea sets of excellent texture were placed.

Ding Xuewei looked like she was about to have a long talk, and both of them couldn't help but be moved by her, and unconsciously followed her footsteps.

Three hours had passed, but Fang Heng's face was not much better, and when he came back, the old man wanted to know more than he could hear anything strange from Ding Xuewei, so he naturally sat on the wooden bench closer to her, leaving the chaise longue to Fang Heng.

Fang Heng, who followed the two of them, looked at the two of them first, and then lay back peacefully.

"Grandma said that this material is called stainless steel, stainless steel has good corrosion resistance, hardness and strength, and the shortcomings are very difficult to manufacture. To create this material, ordinary charcoal is not possible, and coal or gas must be used. ”

"Coal is an ancient plant that has undergone complex biochemical and physicochemical changes buried in the ground and gradually formed as a solid flammable mineral." She has a complicated gaze: "Don't ask me what biochemical and physical changes are, even if I ask, I can't tell clearly... I didn't even understand these two things. Nor is the point, the point is that coal is a black combustible like a stone. ”

"Compared with coal, gas is much easier to understand, and there are many kinds of combustible gases, and the easiest to obtain is called biogas. Although this biogas is more readily available than other gases, it is also more dangerous, and any leak in the pipeline that transports biogas may cause an explosion, and the explosion of combustible gas is very dangerous. After reciting it like a book from heaven, he added: "The pipes that transport biogas can be cast from any material of copper, iron, gold and silver, but the best is rubber." ”

"This rubber is a white sap secreted by the epidermis of a tree called the rubber tree, which is a positive species that prefers high temperatures, sunny and moist places, and is less cold-tolerant."

What does coal look like and what conditions are needed for biogas, Ding Xuewei said very clearly, where to find these things, sorry, she doesn't know.

Ding Xuewei thought about making the old man believe in the existence of the old woman and fear her existence, but she forgot the saying that it is better to travel thousands of miles than to read thousands of books, no matter what time it is, it is the most worthy of the postgraduate entrance examination.

"Black combustibles like stones!" The old man chewed: "Like a stone~"

Compared with coal, Ding Xuewei felt that biogas was feasible, but the old man's attitude made her stunned.

"Elder Yang has seen it?"

If you can find a coal mine, biogas is not a good choice.

Compared to coal, biogas is too dangerous.

Ding Xuewei's attitude looked like he had seen coal, and the old man raised his eyes.

Fang Heng saw that the old man had no idea of explaining, so he said a lot: "The reason why Mocheng is called Mocheng is because there is a special strange rock formation in Mocheng. This rock formation is not only black but also extremely barren, and no vegetation can grow on this rock formation. ”

Ding Xue didn't know if the Mocheng in their mouth was the border city north of Rongshan Mansion, whether the coal was so barren that it could not supply the nutrients needed for plant growth, and the two of them were extremely familiar with the black stone in her mouth was the key.

"Can you bring some to me?" With coal, not only can this stainless steel machete be reforged, but it can also be experimented with to make better alloys and better weapons... The male protagonist's friendship with his own family should be able to save Pandi's life!

Many ideas are just instantaneous.,To provide weapons for the male protagonist, you have to find coal first.。

"If the black rock formation in Mocheng is coal, then this machete can be easily forged, the maximum temperature of coal is 1700 degrees, and the melting point of this steel is 13 to 1,004."

How she determined the temperature of the two is unknown, but a little, the two are more certain.

Her imagination is unusual.

"The kid is going to go immediately." Fang Heng stood up suddenly.

The old man did not stop it.

"What about me?" Ding Xuewei said that she had something.

She didn't know how many black rock formations there were in Mocheng, but she didn't know how long it would take to get to Mocheng from here.

A month and a half allows her to do a lot.

"Old Yang, why don't I go back first, and I'll come over again when Brother Fang delivers coal?"

If before, Ding Xuewei was not sure of the weight of her heart in this old man, and she didn't dare to imagine how to die.

Now, not to say that it won't be done to her, at least not until this machete is smelted.

Ding Xue was slightly confident, and her courage was naturally greater.

The old man was not as good a man as she thought.

"You get down on your knees." He was extremely serious.

Ding Xuewei's heart was shocked.

"The old man is proud, and he has never thought about accepting apprentices. You, the old man gave you a chance. ”

Lao Tzu decided to accept you as an apprentice, you should be grateful to Dade.

Ding Xuewei never thought of apprenticeship, let alone apprenticeship with a blacksmith.

Silently, she raised her arm.

Her action was too obvious, the corners of the old man's mouth twitched, and he was maliciously surprised: "Lao Tzu didn't dislike you, you still dare to put on a face for Lao Tzu." Lao Tzu told you that your grandmother is not in the territory of Great Xia now, don't want to use her to suppress Lao Tzu. ”

A roar every day, begging for tickets, asking for collections...