Liu Tan remembered that greenhouse technology had actually already existed in the Western Han Dynasty, and it was recorded in the "Book of Han".

But when he asked, not only Li Xi but also the people around him looked confused. Liu Tan couldn't help but feel a little strange. After thinking about it carefully, he found that the record was from the time of Emperor Yuan of Han, which was still seventy or eighty years away from now.

Since there is no ready-made one, I have to make it myself.

Fortunately, most of the rooms in this manor, or in other words, except for the rooms for slaves and some warehouses and equipment, basically have underground dragons. Liu Tan only needs to choose one as a greenhouse.

Li Xi, following behind Liu Tan, looked puzzled. "Can this... really make buds sprout and grow in autumn and winter?"

Liu Tan nodded and said, "Yes, as long as the temperature and humidity are met."

Li Xi looked at him blankly and asked, "I am a dull-witted person and do not understand what Your Highness means."

Liu Tan: ...

Come on, there is no concept of humidity and temperature these days.

So the question is, since he has no concept of temperature, how can he control the temperature?

As far as he knew, in ancient times, temperature control relied entirely on experience. Even the person in charge of firing porcelain was an experienced person who could visually observe the flame and judge the temperature by the color of the flame. Such a person generally could not do this without more than 20 years of experience.

Oh, he almost forgot, there is not even porcelain now, or it has not yet developed to porcelain, and now there is more pottery.

The difference between pottery and porcelain lies in firing.

Having said that, there may not be many people nowadays who can judge the temperature based on experience. Of course, the ancient people were wise. They figured out the seasons based on the weather, and it was quite accurate to carry out agricultural planting based on the seasons. However, it would be too difficult to make an accurate judgment without this.

Liu Tan simply asked Li Xi: "Does the Minister of Agriculture have such a talent?"

Li Xi smiled bitterly: "This... Even the Minister of Warmth has heard of this for the first time. I'm afraid that the Minister of Agriculture's Office is not good at this kind of thing."

Liu Tan was helpless. It seemed that he had to do it himself.

If you want to control the temperature, you must first make a thermometer.

Thermometers look simple and are actually quite simple to make.

A glass tube and a little red pigment are all you need.

So now the question is, where can we find glass tubes these days?

The West should have had colored glass by this time, but there was probably no such transparent glass anywhere in the world, not to mention the thin glass tubes that required extremely high skills.

Liu Tan doesn't have time to work on glass. The only alternative now is probably crystal, but can crystal be made into such thin crystal tubes?

It’s not that he has strict requirements, but there is no specific evaluation standard or other comparison these days. The only standard Liu Tan can use to make a thermometer is the boiling temperature of water.

His original plan was to make a model based on the thermometer of later generations, and then put the thermometer into the boiling water to see how high the red liquid in the transparent tube rose, which would be the approximate range of 100 degrees.

Then divide this range into one hundred equal parts to obtain a rough thermometer.

It’s a very simple method. Many children in later generations will be asked to do this when developing their hands-on skills because it is lively and interesting.

But now that he was here with Liu Tan, things were not lively or interesting at all. He realized that without an industrial foundation, he would encounter countless difficulties even if he just did a little handicraft.

One good thing about Liu Tan is that he never gets hard on himself. His knowledge of the Han Dynasty is limited to what is recorded in historical books or found in tomb excavations. Those things are not enough if he wants to live in this era.

Liu Tan thought about it and felt that this kind of handicraft should be under the jurisdiction of the Shaofu. At least he needed to go to the Shaofu if he wanted something.

The only thing he wasn't sure about was whether he could find the Shaofu, so he asked Fu Yu very politely: "Does Curry have any crystals?"

Fu Yu was stunned for a moment: "What are you talking about, Your Highness?"

Liu Tan immediately corrected himself, "It's Shuiyu."

He almost forgot that crystal was called water jade in ancient times.

Fu Yu then said, "What kind of water jade does Your Highness want? Even if Curry doesn't have it, you can go find your wife."

Liu Tan thought that although Chen Ajiao was the queen, she couldn't make this thing happen.

He simply said, "I want to make a hollow water jade tube about the length of a palm, so I need raw water jade."

Fu Yu was a little embarrassed: "I'm afraid I'll have to look for this."

Liu Tan's Curry has no shortage of good things, including jade products, but the problem is that no one will give Chen Ajiao the raw stones directly.

Li Xi beside him said, "The Shaofu should have this item, but I wonder what kind of shape Your Highness wants it to be?"

Liu Tan directly asked Miao Rui to bring a piece of paper and drew a crooked diagram on the paper. He originally wanted to write some words, but at the moment he picked up the pen, he suddenly remembered that Liu Che and Chen Ajiao might not care much about what his handwriting looked like, but Li Xi might know. If he wrote this word, Li Xi might be surprised why it was completely different.

Liu Tan simply put the pen aside and began to explain. Fortunately, this thing was not too complicated. It just needed to be hollow inside and then wrapped with metal at the bottom, so an opening was needed from the bottom, and then the part where the metal and the water jade were in contact had to be sealed strictly to prevent air from leaking in.

Li Xi was stunned and didn't understand what Liu Tan wanted this thing for.

Before, he could understand when Liu Tan asked him to find grape seedlings, and he even understood a little about the grafting and greenhouse technology, but what exactly is this thing for now?

Liu Tan wanted to explain, but the more he tried, the more confused Li Xi became. Finally, he simply said, "It's useful anyway. With it, the grape seedlings have a better chance of survival. Don't ask. If you ask, it means you don't understand."

Li Xi touched his nose. He knew how to fight all his life and was proud of his good fighting skills. He really didn't care much about other things.

He smiled somewhat ashamedly and said, "Your Highness is indeed very knowledgeable."

Liu Tan: ...

After all, this guy has been your "son" for more than ten years. Don't you know that he is knowledgeable and experienced?

Li Xi filled in the key points on the paper. After a moment of contemplation, he said, "Water jade is easy to find, but this one needs to be thin and hollow, so it's probably not going to be easy."

Liu Tan saw that he had no choice but to let them find the raw stones and do it themselves. Fortunately, he was good at hands-on work. Before he came through, he had nothing to do and liked to make clay figures by himself. Otherwise, he would be at a loss now.

What Liu Tan didn't expect was that it was so difficult to find raw water jade. Most of the raw water jade were not transparent enough and had too many impurities. It was basically impossible to make them purely transparent. Liu Tan had even lowered his requirements and didn't need them to be particularly transparent. As long as he could clearly see the water mixed with the red pigment inside, it would be fine.

Well, because there is no pigment, Liu Tan can only use the same color as a substitute. Fortunately, this thing does not have such high requirements for materials, otherwise he would really have to give up at this moment.

Just when Liu Tan was arguing with the thermometer, Lu Xuan somehow learned that he was looking for raw water jade, and came to him with a whole piece of water jade of very high purity.

Liu Tan couldn't help but feel a headache when he saw Aga Mu coming in with a lacquer box.

The golden horse statue he received last time really left a deep impression on him. Not only was the gift valuable, but the lacquer box outside was also worth a fortune.

This time the lacquer box is similar to the last time, except that the decoration on it has become tortoise shell, and the image of a fish is made in an exaggerated way.

Liu Tan looked at the box and asked, "What is this for?"

Lu Xuan smiled and said, "I heard that Your Highness was looking for water jade. I happened to have a nice piece of water jade, so I brought it to you."

As he spoke, he looked at Aga Mu. Aga Mu immediately stepped forward and placed the box on Liu Tan's desk and opened it. This time the lacquer box did not have any sophisticated mechanisms. Aga Mu took out a piece of water jadeite of very good purity from it.

Liu Tan could tell that this rough stone was probably a semi-finished product that had been processed and polished. Its length was slightly larger than his palm, and its width was almost the same, and its thickness was also about the same. It was a fairly large rough stone, and in terms of purity, it was indeed the best he had seen recently.

However, jadeite of this purity should be a very valuable item in this era, especially since it is quite large. Liu Tan was too embarrassed to directly ask to buy it, so he said, "This rough stone is too valuable. I can't accept it."

After hearing this, Lu Xuan looked at Liu Tan intently and asked, "Didn't Your Highness say we were friends? You and I are now close friends, and isn't it natural for friends to help each other?"

Perhaps it was because Lu Xuan's eyes looked so clear, but Liu Tan felt a little reluctant to deny his statement. He simply said, "I'm naturally happy that you're willing to help me, but this crystal is rare even for me, so you shouldn't spend so much money."

Lu Xuan smiled and said, "It's just a personal possession, so what's the harm?"

His smile was truly like moonlight pouring down, illuminating the entire room.

Of course, when it comes to Liu Tan, his mind is filled with: Wow, this is so beautiful.

Even though he and Lu Xuan had met many times, and this wasn't the first time he had seen Lu Xuan's smile, he couldn't help but take a second look each time.

Lu Xuan smiled even brighter after realizing it.

Liu Tan realized that he was about to be startled by a man's distracted laughter, and quickly averted his gaze and said, "In that case, I will not refuse it."

Although he said this, Liu Tan still decided to repay the favor.

His attitude towards Lu Xuan was actually quite complicated. Lu Xuan was a good person, at least he was good to him, so he actually wanted to make friends with Lu Xuan. However, Lu Xuan's identity was too sensitive, and Liu Tan's own situation was also very troublesome. What if in the future, whether it was Liu Ju or Liu Fuling, they came to power and accused him of colluding with foreign countries? Who would he turn to for justice?

So even though he felt guilty, he decided to draw a clear line between himself and Lu Xuan.

It must be said that the water jade sent by Lu Xuan was indeed very useful, but he was also very curious why Lu Xuan happened to have such a water jade in his hand, and he had never found it before?

He casually said this that day, and Bi Gao said cautiously: "Your Highness...you should go to the Minister of the Household for this. Li Xi...how good can he be?"

Liu Tan was stunned for a moment before he realized that he seemed to have been in the wrong place.

As an agency dedicated to serving the royal family, the Shaofu must have a lot of good things, but Li Xi... was just a Guannei Marquis before. Although he is also a noble, his home and the places he can find are definitely not as good as the Shaofu.

Liu Tan's mouth twitched as he turned to look at Bi Gao and asked gravely, "Why didn't you remind me?"

Bi Gao smiled awkwardly. He originally thought that Liu Tan did not want to alarm the emperor and the empress. Who would have thought that he really did not think of sending someone to the Shaofu to ask for it.

Liu Tan looked at the semi-finished product in his hand. He had been manually grinding this crystal tube for several days. Although Bi Gao and the others said they would help, Fu Yu and Cen You did not have enough strength, and Bi Gao and Miao Rui were not careful enough. After breaking two of them, they were driven aside by Liu Tan.

Forget it, I’ve already used it, what else can I do?

After the thermometer was ground, Liu Tan directly handed the task of making the thermometer to Miao Rui, asking him to find someone to make it and also told him the operating instructions.

He had a thermometer, a greenhouse, and strong grape vines. Everything was ready except for the east wind. Then Liu Tan discovered that he had to do the grafting work himself.

Liu Tan...Liu Tan could probably imagine that in the future there would be rumors in the martial arts world that the fifth prince liked farming.