The gift he prepared for his nephew and grandson can be regarded as a hard time for Li Yuanjia.

He definitely can't make a diaper or something, after all, the requirements for the technical level of that thing are too high, even if he is given ten years, I'm afraid he won't be able to get it, and this is the emperor's grandson of the Tang Dynasty, I'm afraid the diapers he usually uses are made of silk, who still rarely uses paper?

As for the bottles, pacifiers and milk powder or something, it's not worth mentioning, not to mention the royal family, these days, the big aristocrats are raising their children with real nurses, one is not enough for two, two is not enough for three, pure natural and pollution-free, and by the way, it also comes with the bonus of immunity......

So after thinking about it, Li Yuanjia can only "design" some fun gadgets.

For example, the cradle that is erected with a stand, the simplest version of the trolley, which has a small mechanism that can be changed from lying down to sitting, and the wind chimes that hang on the bed to attract children's attention and exercise their hearing and vision......

The craftsmanship of the little carpenter Chen Mu at home is becoming more and more exquisite.

If it weren't for the fact that these things were too time-consuming to make, and the capacity of the Chang'an market in this year was really limited, Li Yuanjia even had plans to let him go out and open a small shop. However, considering the influence of various factors, and considering that he also used this kid in his daily life, Li Yuanjia finally dispelled this idea.

Merely......

On the penultimate day of the end of the month, when he was thinking about what to bring to the spring outing tomorrow after returning from the Daxing Palace, Chen Mu walked in with an excited face under the leadership of the housekeeper.

"King, we've made it!"

“…… What do you mean? ”

Li Yuanjia, who was a little careless, was stunned when he heard Chen Mu's voice, and subconsciously blinked: "What did you do?" What did I let you do? ”

"Waterwheel, King!"

Seeing Li Yuanjia's appearance that he couldn't think of anything, Chen Mu suddenly became anxious: "When I was in Luzhou a few years ago, didn't you let us make those two kinds of waterwheels together?" It took years before we finally made it! ”

"Water wheels? That's right! ”

Hearing Chen Mu say this, Li Yuanjia patted his thigh and immediately remembered.

Indeed, there is such a thing!

After arriving in Luzhou, Li Yuanjia once remembered the kind of waterwheel often seen in TV and movies, without human drive, the power of the river can make it turn on its own, and then send the river water to the shore little by little. The other is to let Chen Mu transform and improve the existing overturned car in this era, and the waterwheel driven by human power is the kind of thing that two people stand on it and step on to pump water out of the river.

In order to get these two things, Li Yuanjia also deliberately asked Han Shan and them to find a carpenter who could build a rollover car.

It's just that a few years have passed unconsciously, and he has forgotten about it.

So when Chen Mu just came over today, Li Yuanjia also froze for a moment, and then reacted. Then, naturally, he was surprised and delighted, and stood up from his chair: "Did you make a real thing or a model?" In what place? ”

"Back to the king, the cylinder car just made a model."

Under Li Yuanjia's "Dun Dun Teaching", now that Chen Mu has known the meaning of the model, he naturally replied immediately: "If you make a real thing, it will be too big and it will take too long, so we haven't done it yet...... But we've already made the keel waterwheel, and it's in the farm just outside the city. ”

The cylinder car can actually be large or small, depending on the need, but no matter how small the real cylinder car is, it is also a big project for a few carpenters, so

Chen Mu: All the people have been trying to make are miniature models. Now that I have finally succeeded, I will come to Li Yuanjia to report the good news immediately, and the real thing naturally has not started at all.

"Good, good!"

The right fist slammed into his left palm, and Li Yuanjia laughed and said, "You go back first, tomorrow morning, I'll go and see what you have done!" ”

"Yes, my lord."

Seeing that Li Yuanjia attached so much importance to this matter, Chen Mu naturally left, and he knew that once the king was satisfied with the waterwheel made by a few of his people, a generous reward would definitely be indispensable.

"Hoo ......"

After Chen Mule went back, Li Yuanjia let out a long breath, and his mood was really happy.

The success of the research of these two types of waterwheels came at a good time.

Whether it is a keel waterwheel or a barrel car, in fact, the structure is not too complicated, after all, how difficult can it be to use things in ancient China? Moreover, these things actually had physical objects in the Tang Dynasty, or they already had a prototype, and the two carpenters Han Shan specially found had a lot of experience in this. But even in this case, coupled with the detailed pictures drawn by Li Yuanjia himself from memory, it still took the gang several years to make a model......

Although he almost forgot the thing he asked Chen Mu and them to study, but now that he succeeded, Li Yuanjia immediately remembered his original plan: with the Quyuan plow, an epoch-making agricultural tool that can greatly reduce labor, and a light and simple waterwheel, the combination of the two will have an immeasurable impact on the agriculture of the Tang Dynasty.

Obviously, the Tang Dynasty is now vast and sparsely populated, and more land can be cultivated under the same conditions with a curved plow, but because there are not enough irrigation facilities, a lot of land far from water sources is still barren. And it is this situation that makes the role of the Quyuan plough simply unable to play to the extreme.

After looking at the blue sky for a while, Li Yuanjia couldn't help but smile bitterly and shook his head.

The waterwheel is much more complicated than the zigzag plow.

Not to mention the corners and corners of the Tang Dynasty, even under the state capitals of the Central Plains, many peasants have never even seen it. And this is still the case when the imperial court has spent a lot of effort to promote, and each state and county has sent a drawing.

The inefficiency and the difficulty of the process are really outrageous!

The carpenters of this era wanted to master the art of making waterwheels, and they didn't even think about it without a few years of hard work. And if you build a waterwheel, Chen Mu and the others will have to work for a month!

If these two waterwheels were really simpler and easier to build......

Under the surging heart, Li Yuanjia couldn't help but get up and walked outside the door, looking at the distant sky. In fact, he has now understood that in this era of extremely backward productive forces and extremely poor communication, the role of any good thing must actually be discounted.

"Alas!"

It's like a zigzag plow, after such a good thing appeared, where is it being promoted now?

After a brief period of euphoria, there was soon a melancholy.

In fact, after the appearance of Quyuan plow, Li Yuanjia had already discovered its limitations.

So after being depressed for a while, Li Yuanjia secretly made up his mind: "In the long run, it is still necessary to cultivate a group of real talents from an early age......

And......

Therefore, Li Yuanjia is thinking about the problem now, and he often starts in ten years, and the impact of things like waterwheels must be considered in 50 years.

"After fifty years, how many new fertile fields can Datang add?"