In the small firewood shop, Zhang Shijie's eyes wandered, and from time to time he fell on Su Yu, trying to see something.

But he was disappointed, and the young man in front of him didn't leak. It's hard to see what he's thinking.

Su Yu understood what Zhang Shijie meant as soon as he pondered it, so he pretended not to know and didn't speak.

At this time, whoever speaks first will fall into disadvantage.

In the end, Zhang Shijie guessed that Su Yu probably saw his thoughts, so he took the lead in speaking.

"I heard that Su Gongzi just broke through the Wuhuan tribe, how can he be elegant today and come to Liaodong County?" Zhang Shijie said with a smile.

Su Yu showed a bitter look and said: "It's not about money, it's not about money, it's not about seeing what way to get rich, there is no money to pay military salaries." ”

Zhang Shijie's eyes flickered, and then he laughed: "I see, Su Gongzi cleared the mountain bandits of the Hidden Dragon Pavilion and let my Zhang family caravan not be robbed by the mountain bandits, Zhang should have something to say." ”

After a pause, Zhang Shijie muttered: "50,000 gold, Zhang gave 50,000 gold as a little thanks." ”

Su Yu was overjoyed but didn't show it, and arched his hand and said, "Then thank Mr. Zhang and let Yu's group of brothers have food." ”

"It's okay, my Zhang family still has some money."

Zhang Shijie has something to say, Su Yu smiled and did not have an interface.

Is this a rejection? Zhang Shijie's eyes darkened, and he quickly regained his luster and changed the topic.

Sighing, he looked at the snowflakes that kept falling outside, and he looked worried.

"Zhumen wine and meat stink, there are frozen bones on the road, and it is snowing again, and now the price of firewood is so high, many people will freeze to death this winter!"

"The price of this charcoal is high, but the weather is very cold, I wonder if Su Gongzi has any way to solve the problem of ordinary people's heating?"

Zhang Shiping asked with a hint of expectation.

"In fact, the problem of heating is very easy to solve, this charcoal is expensive, why not use coal?"

Su Yu replied almost without thinking.

"With coal?"

As soon as Su Yu's words fell, he was stunned for a moment, and then ecstatic, yes, he used coal. Damn, I actually forgot some of the strategies from my previous life.

He couldn't wait to knock his head open, too many things have happened after being reborn, and it is not an exaggeration to say that he has reached the sky in one step.

Holding an army in his hand, and a golden finger against the sky. He slacked off and bred pride, and after realizing it, Su Yu broke out in a cold sweat.

It was too smooth, which made him feel less in crisis and vigilant. Su Yu took a deep breath, realized that there was something wrong with his mentality, adjusted very much, and warned himself to act safely.

At the same time, hearing his words, Zhang Shiping and even Dian Wei were slightly dumbfounded, thinking that Su Yu would be able to come up with some good way, but they didn't expect Su Yu to come up with such an idea.

"After all, he's still too young, doesn't he know that the smoke from this coal is poisonous?"

Zhang Shiping looked at Su Yu and couldn't help but shake his head slightly.

The people behind him frowned slightly, glanced at each other, and saw suspicion in the other party's eyes.

"This son, this coal is indeed very cheap, and a load of coal only costs a few dozen yuan, but does Childe know why everyone uses charcoal instead of coal?"

The shopkeeper on the side really couldn't help it, the boy in front of him really met the standards of a scholar, he only read the books of sages and sages, and he didn't even know about the poisonous gas produced by coal.

"Of course I know that burning coal will produce poisonous gas, which is easy to kill, and coal should not be ignited, which is extremely inconvenient to use, compared to charcoal, it is much more convenient and will not produce poisonous gas."

Su Yu looked at everyone, smiled and said confidently.

"Childe is right, since Childe knows that this coal will kill people if it is used, why do you want everyone to use coal, isn't it clear that everyone will be sent to death?"

The shopkeeper was slightly stunned, he didn't expect Su Yu to know so clearly.

"Although coal will produce toxic gas when burning, this poisonous gas is easy to kill, not easy to ignite, inconvenient to use, but this coal it burns for a long time, high heat, whether it is used for heating or cooking, boiling water, etc.

"We have an old saying called seeking advantages and avoiding disadvantages, and there is also an old saying that taking its essence and removing its dross, the advantages of this coal are numerous, as long as we can solve the toxic gas produced when coal is burned, we can naturally use it with confidence."

Su Yu replied with a smile.

"But how can this coal be burned to produce poisonous gas?"

When Zhang Shijie heard this, he hurriedly asked, and everyone else also stared at Su Yu one by one, if Su Yu can really solve the problem of toxic gas when coal is burned, it will be very beneficial to the country and the people.

"To solve the problem of toxic gas produced when coal is burned, we must first understand why this coal produces toxic gas when it is burned, and why this charcoal does not produce toxic gas."

Su Yu looked at Zhang Shijie, then came to the place where the charcoal was stacked on the side, picked up a piece of charcoal and said: "This coal and charcoal are both black, and they can both be burned for heating, which shows that in essence, they are all the same, and they are both composed of something that can be burned for heating." ”

"However, the burning of this charcoal does not produce toxic gases, and the burning of this coal produces toxic gases, which shows that there must be something else in the coal, and it is this kind of thing that produces poisonous gas when burning, and once people inhale this poisonous gas, they are easy to be poisoned and die."

Su Yu analyzed slowly, and the others also nodded slightly when they heard Su Yu's words, thinking about it carefully, it seemed that what Su Yu said was very reasonable.

"You're saying that we just need to get rid of the toxic stuff in the coal and be able to use it with confidence."

Zhang Shijie rolled his eyes, thought about it and said.

"That's right, we only need to remove the toxic things in the coal, and we can use the coal for heating and fire without worrying about poisoning."

Su Yu nodded solemnly and said: "The toxic substance contained in this coal is sulfur, and sulfur dioxide will be produced after sulfur is burned, and this sulfur dioxide is a toxic gas, and excessive inhalation can easily poison and die." ”

"I know the sulfur, but I don't understand the sulfur dioxide."

Hearing Su Yu's words, Zhang Shijie hurriedly asked.

"This sulphur dioxide can be understood in this way, it is a new thing formed after the combustion of sulphur, just as this charcoal will form ash after burning, and after this coal is burned, it will also turn into ash, and it will also produce the toxic gas sulphur dioxide."

Su Yu touched his head, people in this era don't even have the most basic understanding of the natural science community, so there is no way to tell them about sulfur dioxide and other things, and after thinking about it, they can only briefly let them know this meaning.

"I see~"

Sure enough, as soon as Su Yu explained like this, the others nodded their heads one by one to express their understanding.

"So how do you get rid of the sulfur in the coal?"