As early as the Warring States Period, saltpeter was a commonly used traditional Chinese medicinal material and could be purchased in many drug stores.
And the homemade method is also very simple.
Every year when the air is crisp and clear in autumn, the crust-like or salt-flower-shaped clods of earth covering the ground and in the corners are saltpeter mines.
Just break up the soil, add water to soak it for a while, pour out the soaked water, boil or dry it until it is completely dry, and the remaining crystals are saltpeter.
"You can also go to the medicine shop to buy some saltpeter when you go back. You can turn water into ice by following my method!"
After hearing what he said, Xiao Sizi nodded repeatedly and had a great time playing with the small bag.
The three of them stayed in the courtyard at the back of the mountain for nearly a day.
After dinner, when the sun is about to set.
The whole family reluctantly said goodbye to Su Chen and returned to Chang'an by carriage.
After returning to the palace, His Majesty Li Er was waiting for his idle daughter in the Li Zheng Hall as before.
After a while, Princess Changle walked in holding Si Zi.
"Daddy, grandma!"
"Daddy, grandma!"
His Majesty Li Er asked with a smile: "What did you do in Sujiazhuang today?"
Princess Changle did not answer his question, but asked: "Dad, can you build a dam to block the Yellow River so that it can't come out?"
Upon hearing this, His Majesty Li Er was stunned.
Block the Yellow River?
How can there be such a strong dam in this world?
Not knowing why his daughter suddenly asked such a strange question, His Majesty Li Er shook his head and said, "No, why do you ask like that?"
After Princess Changle heard what he said, she whispered back: "Brother Su Chen can."
His Majesty Li Er was stunned again. Before he could recover, Princess Changle continued to ask: "Dad, can you turn water into ice?"
His Majesty Li Er continued to shake his head.
"There is ice in the cellar in our palace, but it was all saved from winter."
Princess Changle nodded and said, "Brother Su Chen can."
His Majesty Li Er has finally come to his senses now!
Is that brat Su Chen and his daughter going to lock up Huang He?!
Not caring about being jealous, His Majesty Li Er hurriedly asked: "That boy Su Chen...does he want to build a dam on the edge of the Yellow River?"
Although it is bizarre to be able to turn water into ice, if it happened to Su Chen, His Majesty Li Er would not find it strange at all, and would think it was just a trivial matter.
After all, if Su Chen is planning to build a dam as he guessed, then that will be a real big deal!
Remembering what Su Chen said yesterday that he was busy with big things recently, His Majesty Li Er suddenly couldn't sit still!
Could this bastard want to cheat him out of money again?!
"Yes, Brother Su Chen said that we will build a dam so that floods will never happen again in the Tang Dynasty." Princess Changle nodded with a somewhat proud tone.
It’s over!
Upon hearing this, His Majesty Li Er felt as if he had been struck by lightning!
Building dams is a good thing!
Su Chen said he could completely eliminate the flood, and he didn't doubt it!
but!
How much will it cost to build a dam along the Yellow River?
According to Su Chen's character, can he pay for it himself?
Combined with Su Chen's previous remarks, His Majesty Li Er understood instantly!
The reason why Su Chen is eyeing the trophies brought back from Tubo and Goguryeo is probably because of this!
Thinking of this, His Majesty Li Er suddenly felt his eyes turning black!
Something bad is happening!
In the second year of Zhenguan, a tributary of the Yellow River burst its banks, causing great casualties to the people.
The flood occurred mainly because of excessive rainfall, which caused the dams to be washed away.
His Majesty Li Er knew very well that the dams built by the former Sui Dynasty had not been repaired for more than ten years.
The dykes are no longer as strong as before, making it difficult to withstand sudden floods.
But at that time, national power had just begun to develop, and even if you wanted to practice cultivation, you had more than enough ambition but not enough power.
Although the national treasury is now richer, it cannot spend all the money on building dams!
According to His Majesty Li Er's idea, wherever there is a problem with the dam, it should be repaired.
Step by step, we will strive to repair the entire dam along the Yellow River within ten years.
But based on His Majesty Li Er's understanding of Su Chen, that boy would never accept such slow progress!
If you let him do the cultivation, it will be done in one step!
In this way, the money spent is definitely not small!
If Su Chen really set his sights on him, would he have to empty out the entire treasury?!
"What else did the boy say?"
His Majesty Li Er quickly asked: "Did he say that all the dams along the Yellow River would be rebuilt?"
"Brother Su Chen has this plan."
Princess Changle nodded.
Upon hearing this answer, His Majesty Li Er instantly felt that he was not feeling well!
He was indeed right!
That boy Su Chen is really going to do something big this time!
"Did that little bastard tell me how to fix it?" His Majesty Li Er calmed down and continued to ask.
"Brother Su Chen said that we need to use iron bars and cement to repair it, so that we won't be afraid of being washed away by floods." Princess Changle said seriously.
“Using iron to build dykes?”
His Majesty Li Er was immediately confused.
"Where can he get so much iron for him?!"
"Even if there is, how much will it cost?!"
Seeing that His Majesty Li Er was a little excited, Princess Changle came over, gently stroked his back, and said: "Dad, not all promotions are made by Iron Lai Xiu."
"Brother Su Chen said, first use strong iron bars to make a fishing net shape, and then fill the outside with cement and sand. Such a dam can definitely shut down the Yellow River."
Hearing this, His Majesty Li Er breathed a sigh of relief.
"That's not too outrageous."
Then, he said with some worry: "Did that boy Su Chen say he was going to trick dad?"
"Brother Su Chen didn't say anything."
Princess Changle shook her head and said, "Don't worry, Dad, Brother Su Chen is not messing around!"
"Brother Su Chen said that if the dam is not repaired quickly, there will be a flood and fire in two years."
"At least more than thirty states and counties will be flooded. In that case, all the food in the past two years will be white-grown!"
His Majesty Li Er was directly shocked by her words!
Flooded more than 30 state capitals?!
Such floods have not happened many times in history!
Although he couldn't believe it, since the words came from Su Chen's mouth, he had to pay attention!
His Majesty Li Er quickly asked: "How did that kid know about this kind of thing?"
Princess Changle replied in a soft voice: "Brother Su Chen said that these were all calculated by him."
Calculated?
That guy Su Chen can also perform deductions?
When he first heard this, His Majesty Li Er still didn't believe it.
