In Liu Tan's impression, the only thing that does not freeze in cold places is probably sea water. Of course, sea water will also freeze if the weather is extremely cold.

The climate in the Northern Border this year is cold for everyone coming from Chang'an, but according to local people, it is already a very warm winter.

In this case, the only lake that does not freeze is a lake with a very high salt content, which is the legendary salt lake!

But the problem is that this lake is very close to Shuofang City. It wouldn't take him long to go back and forth. If it were a salt lake, it would have been discovered long ago. How could there be no record of it at all?

But no matter what, it’s better to find out first.

Liu Tan's original intention was to ask the people around if they knew there was a salt lake here, but these knights, each one more ferocious than the other, turned around and ran back. After a while, they came back and said, "I tasted it, it's salty!"

As soon as these words came out, everyone was very excited.

In this era, it may be an exaggeration to say that salt is better than gold, but it is not far behind.

A pound of salt is not as expensive as gold, but it is also extremely expensive. The most important thing is that the output of salt is actually much higher than that of gold!

If a salt mine could be discovered, it would be no less valuable than a gold mine.

Liu Tan was a little bewildered: "There's a salt lake here, why hasn't anyone discovered it before?"

It shouldn't be like this. The people here are so poor that even now every household doesn't have much salt, which is only enough to meet the normal needs of the human body. This is still the case for families with good conditions. If the family conditions are not good, then it really is... Do you know about salted cloth strips?

According to legend, you should soak the cloth in salt water, then lick the cloth after taking a sip of porridge while eating, and that is the dish.

The salt shortage is so severe. If there were a salt lake, how could the local people let it go?

Not to mention that there were no salt lakes before, the formation of a salt lake requires thousands of years of sedimentation.

Liu Tan remembered that salt lakes are formed when the evaporation of lake water is greater than the precipitation. Thinking about it this way, the climate in Shuofang City is just right.

Seeing Liu Tan standing there without saying anything, Wei Deng quickly said, "Your Highness, please get some water to boil salt first!"

Liu Tan: "Hmm? Boil salt?"

Wei Deng said happily, "It just so happens that we have honeycomb coal. It's much more cost-effective to boil salt than to use firewood."

Liu Tan suddenly had a headache: "What are you cooking?"

Isn't it a rip-off to cook salt in a place with such abundant sunshine?

Liu Tan said directly, "You guys go ask around to see if there are any legends about this lake. The rest of you go find a spot nearby and build a brine pond as I've described... Forget it, let's go back first. I need to make the detailed arrangements."

Liu Tan rubbed his forehead. The cold wind made his head hurt a little. This salt lake really caught him off guard.

When he returned, Liu Tan did not forget to send someone to inform Liu Che. He originally went to find a place for Liu Che to play, but unexpectedly found a place similar to a salt lake. It was getting late, and it should be too late to play, so of course he had to send someone to inform him.

Liu Tan's discovery of the salt lake directly alarmed Liu Che.

If it were in the past, he would definitely not care if Liu Tan said he had something to deal with, but after going out for a walk and bringing back such news, Liu Che was a little surprised.

So he went to Liu Tan's study in person, where Liu Tan was discussing something with Huo Guang.

Hearing that Liu Che had arrived, he immediately went out to greet him. Looking at the man following Liu Che step by step, without any trickery or coquettishness, he twitched the corner of his mouth and shouted to Liu Che, "Father."

Liu Che nodded and asked, "I heard that you discovered a salt lake? How did you find it?"

He had heard before that Liu Tan discovered coal mines, copper mines, broken gold mines, iron mines and cinnabar mines by just pointing a few times on the map, but in the past he basically just treated it as a story.

Even if one thinks that Liu Tan is a god who has descended to earth, one would doubt how accurate his predictions could be, especially since he had previously said that Qi and Changyi should have coal. But until now, Liu Fuling and Liu Bo have not found any coal mines, let alone coal mines, they haven't even found any coal slag!

So Liu Che originally thought that Huo Guang was trying to create a divine persona for Liu Tan in order to intimidate the Huns.

The Huns also had faith, and were even more devout than the Han people.

The Han people usually worship when they need to, or only during the New Year, but the Xiongnu people are said to mention their gods three times a day and never stop talking about them.

In this situation, having a God-King on the opposite side will definitely bring pressure to the Huns.

Now it was the first time that he personally experienced Liu Tan discovering a mineral, and it was a very rare salt mine, so he couldn't help but feel curious.

Liu Tan explained, "I made an ice sled before, but since I wasn't sure if it would work, I took Wei Deng to test it out. I made some modifications midway through, and after the test, the ice on the lake I was testing on was broken. I wanted to find another lake so I could let Father try it out, too. Unexpectedly, we found what looked like a salt lake."

Liu Tan still hasn't dared to say that it's a salt lake. What if it's just because of some special circumstances that it hasn't frozen over? What if it's because of geothermal heat?

However, after the cavalry said that the lake water was salty, this possibility became infinitely closer.

Liu Che asked, "How did you ask them to find it?"

Liu Tan was stunned for a moment. "Just... find a lake on the map and ask them to go see it."

Liu Che's eyes suddenly became complicated. He looked at Liu Tan for a long while before patting him on the shoulder and saying, "Look at the map more often when you have nothing to do in the future."

Liu Tan was a little slow to react and couldn't help but laugh and cry: "This... is an accident."

Huo Guang said quietly, "You've had too many accidents. How about choosing a place every month?"

Liu Tan said expressionlessly, "Didn't you ask me to choose a location before? Are there mines in those places?"

Huo Guang thought for a moment and said, "Yes, Your Highness must have done this unintentionally."

Liu Tan was helpless, so Liu Che sat down and said, "Go on with what you were discussing just now, don't bother me."

Liu Tan was suddenly stuck. Being interrupted by Liu Che, he really forgot what he was about to say. He looked up at Huo Guang, who reminded him, "Your Highness just said that he wanted to build a brine pond."

Liu Tan came back to his senses. "Oh, yes, a brine pond is actually just a shallow pond. The bottom of the pond is compacted, and then a diversion channel is made to the salt lake. After the lake water is diverted, the water stops flowing when the pond is full, and then it is left there."

Huo Guang looked up at Liu Tan and asked, "Leave it alone? Don't worry about it?"

"Don't worry about it. Just go and collect the salt in a few days."

Liu Che suddenly asked, "Don't need to cook?"

Liu Tan explained, "Just dry it in the sun. There's plenty of sunshine in the Northern Territory, so there won't be any problems."

Liu Che still looked unconvinced, so Liu Tan turned around and said, "Go get some salt water."

Someone immediately took the order and left. Liu Tan placed the salt water in a wine cup and threw it outside. He then said, "Let this wine cup dry in the sun. The water inside will slowly dry up and turn into a layer of salt."

Liu Che was a little curious and immediately sent someone to keep an eye on him. Liu Tan looked at the young eunuch in charge of the watch with sympathy.

Fortunately, although it is winter now, the winter in the Northern Territory is drier, so it doesn’t matter even if the sun is not so hot, the moisture inside will evaporate quickly.

Huo Guang said: "If it is so easy, then this method..."

How many people's worldviews can be overturned by this method?

Liu Tan turned to look at Liu Che, who said without hesitation, "Send people to enclose the lake. This method must not be spread to anyone else!"

The method was come up with by his son, so naturally it should be used by his son to make money. Even the royal family would not selflessly spread it publicly.

Liu Tan hesitated for a moment but did not refute. Nowadays, even if he spread the word, people might not lower the price of salt by using this method. It is more likely that they would use this method to save money, but the price of salt would remain the same, just to plunder money.

Liu Tan said, "Oh, by the way, make sure the people of Shuofang City get salt at half the current price next year."

He didn't know how big the salt lake was. If possible, he would like to benefit the entire Northern Territory, but he decided to take it step by step.

Huo Guang looked up at Liu Tan without saying anything. This salt lake was discovered by Liu Tan and his men, and the method was also provided by him. It can be said that this salt lake basically belongs to him. He can sell it for any price he wants, and it is not Huo Guang's turn to object.

Liu Che, standing by, was unhappy. "How much money do you have? You're so extravagant! Look at what your palace looks like? The best place is actually the garden of the iron-eating beast!"

Liu Che was very unhappy. How could his son live in a place worse than that of an iron-eating beast?

Liu Tan glanced at him blankly: "Now... it's already very good."

This palace has really satisfied all his wishes. His biggest wish before traveling through time was probably to have a villa with a large garden, and it would be even better if it had a swimming pool.

Now the palace basically satisfies all his wishes and even exceeds his imagination. He doesn't know why his palace always seems to be disliked.

Liu Che suddenly felt extremely regretful for sending Liu Tan out of the palace. Let's see what kind of person he would become outside.

But he was also wondering why among so many princes, the style changed when it came to Liu Tan?

All the princes, including Liu Fuling and Liu Bo, had tried to restrain themselves as much as possible when Emperor Wu of Han came to visit them, so as to appear less extravagant, but Emperor Wu of Han could still see how extravagant their lives were.

And Liu Tan... Liu Che heard that the musicians and dancers in his palace only appeared when entertaining guests, and he never used them when he himself ate!

Liu Che originally wanted to give Liu Tan money and let him spend it as he pleased, but now it seems... he decided to change his approach.

So Liu Tan watched in amazement as Bu Fan, who was beside Liu Che, and the palace servants began to busily prepare the palace for him.

Huo Guang slipped away upon seeing this, leaving Liu Tan helplessly looking at Liu Che. Just as he was about to say something, Miao Rui came over and said, "Your Highness, the man sent by General Li to deliver sand to you has arrived."

Liu Tan's eyes lit up after hearing this, and he rolled up his sleeves: "Great, you're finally here."

Liu Che felt like he was dreaming of last year. "No, why did you ask Li Buyan to bring you sand?"

Liu Tan said happily, "Crystal windows are too expensive. If you use them in Weiyang Palace, there will surely be people who will dissuade you. I want to make something cheaper and more translucent to replace them."

Liu Che looked skeptical: "Made of sand?"

Liu Tan was a little uncertain: "It should be possible. In fact, it shouldn't be sand, but there is that thing in the sand. I can't say for sure. We won't know until we do it. But don't worry, I won't do it these days. I'll take you to play ice sled tomorrow after you return to Chang'an."

When Liu Che was here, his task was to play with Liu Che.

Liu Che lowered his head and thought for a while before saying, "Then... I will go back a few days later."

Liu Tan: ?????