To be honest, the toilet should be simpler than anything he had made before, at least he didn't have to make some byproducts first.

Well, I guess so.

Liu Tan took the charcoal pencil and drew the general shape of the toilet on the paper, and then the arrangement of the internal water channels.

He thought about the vortex siphon and jet siphon for a long time. Logically speaking, the jet siphon is better, but in terms of saving water resources, the vortex siphon is definitely better.

After hesitating for a while, he thought it would be better to make both. After all, the jet siphon is a vortex siphon with a jet secondary channel added.

Therefore, if you want to make a jet siphon, you must first make a vortex siphon.

In fact, the pipes of a siphonic toilet are not difficult to design. The first is the water flow hole, which is the easiest. It is connected to the water tank and then goes around the entire toilet. There are many small holes in the middle for water to flow out. Then there is the sewage pipe below, also known as the water seal. It is a curved shape. If you really want to describe it, it looks a bit like a human ear.

After designing all these, Liu Tan did not rush to work on the flushing device of the water tank, but first asked someone to build it according to the shape of this cross-section.

But when it came to building it, I encountered a very serious problem - what materials to use.

According to current toilet materials, wood is generally used. However, after Liu Tan traveled around the Northern Territory, he felt distressed wherever wood was needed - there was no other way, there was little wood in the Northern Territory.

And if it really becomes popular, people like the nobles will definitely use the finest wood lavishly. If something like using rosewood to make toilets appears, even if Liu Tan is rich, he will still feel distressed!

So he subconsciously wanted to make it into ceramics. After all, ceramics would be more suitable for future generations. No matter how valuable ceramics are, they are just made of kaolin. The difference lies in the labor.

In fact, ceramics in this era already had the simplest primitive porcelain, but it was not widely used because it was not beautiful enough. The nobles disliked its ugliness, and the common people did not find it as cheap as pottery, so its development was very slow.

However, one of the biggest reasons why the original porcelain was rough was that the firing temperature was not high enough.

Think about it, what fuel was used in the past? Firewood. The conditions required to achieve high temperatures were too harsh.

So Liu Tan never thought about improving ceramics, but now it’s different, he found coal.

Coal can provide much more heat than firewood, so firing ceramics will become much easier.

Liu Tan asked someone to get him a copy of the original porcelain production method so that he could see how to evolve it based on this.

It has to be said that it is much easier to evolve anything that already has a basic form than to create something out of nothing.

Because Liu Tan only knew the shape and simple principles of many things, he had to try all the basic things bit by bit, which was actually a waste of time.

Of course it is much better than groping without knowing the purpose, but it is not as good as it is now.

For example, the steps of washing, throwing, printing, sharpening, drying and carving in the production of primitive porcelain are actually no different from those of later porcelain.

Maybe there are some differences in the techniques, but... Liu Tan can't tell!

His deepest understanding of ceramics comes from his experience in an open-type porcelain kiln. It is true that he went through the entire process from beginning to end, but it is also true that he has no idea whether the technique is correct.

Anyway, the finished product is ugly.

With these as the foundation, the key changes Liu Tan needed to make were in glazing and firing.

The most important thing in glazing is the glaze quality.

Of course Liu Tan has not studied this, but it doesn’t matter, the ancients have studied it.

He clearly remembered what Zhu Yan, a Qing Dynasty scholar, wrote in his "Tao Shuo": "Glaze cannot be made without ash. Ash comes from Leping County, 70 kilometers southeast of Jingdezhen. It is made from blue-white stone and phoenix tail grass, and then washed with water."

He didn't care where Leping County was, the main thing was the following sentences, the blue-white stone and phoenix tail grass.

Among them, blue-white stone is limestone, or more precisely, slaked lime, and phoenix tail grass is a kind of plant.

As for why this plant was used, and what kind of chemical reaction would occur when this plant was combined with quicklime... Liu Tan knew nothing about it, and he didn't need to know. Anyway, he just wanted a finished product, not to educate the Han people about the origin of ceramics.

My only concern now is whether the plant called Pteris serrata exists today, or if it does, is it called that? Can we actually find it?

He is now calm about having to start searching for something like looking for a needle in a haystack again.

The only thing that made him a little embarrassed was that when people asked him what the grass looked like, he was also at a loss.

He had never seen a phoenix tail grass before. Fortunately, the name of the phoenix tail grass was named after its shape. Liu Tan reluctantly drew the shape of a phoenix tail, uh, to be exact, a peacock tail. He had never seen a phoenix tail before. In his impression, the phoenix tails in many paintings were basically deformations of the peacock tail.

After Bi Gao picked up the paper, a hint of confusion crossed his face. He and Miao Rui muttered to each other for a while. Liu Tan raised an eyebrow and asked, "What are you two whispering about?"

Bigao said cautiously, "Your Highness, it's nothing, we just saw this thing that seems a little familiar."

Liu Tan was a little surprised: "Look familiar? Have you seen it before?"

Bigao didn't dare to say anything, but just said, "It's a bit like that. When I was a child, this kind of grass grew by the well at home. We called it well grass."

Liu Tan was slightly stunned, then slammed the table and said, "Yes, yes, that's it."

Phoenix tail grass, also known as golden cocktail, chicken foot grass, and well fence grass, is basically called whatever it looks like.

Bi Gao was happy to be able to help Liu Tan, but then he felt a little worried: "Your Highness, there is this kind of grass in Chang'an, but it is afraid of the cold, so it may be difficult to find now."

Liu Tan felt a little worried. According to Big Gao, this kind of grass should like shade and moisture, otherwise it would not grow by the well.

In this way, the Northern Country can exclude some areas, as the humidity there is not enough to support its growth.

But after New Year's Day, at the latest after the 15th, he might have to go back. It would not be appropriate for him to stay in Chang'an for several months or even half a year later.

If that didn't work, I could only control it remotely, but that was too much trouble. Asking someone to deliver the grass? Traveling thousands of miles just to get some phoenix tail grass?

Miao Rui, who was standing by, suddenly said, "That might be the case. There are many dragons in the palace, so maybe they have grown in some places."

Liu Tan's eyes suddenly lit up, and he quickly mobilized people to look for phoenix tail grass.

You know what, in the end I actually found quite a few, of course this number is specific to this season.

The next issue is the proportion of the glaze formula. At this time, Liu Tan particularly hated the fact that the ancients never wrote detailed data in their books. None of them had any rigorous spirit. They only said what to use, but you should tell me clearly how much to use!

This way he doesn’t have to try it himself, he just needs to memorize it!

In a fit of excitement, Liu Tan wanted to go into battle himself, but Miao Rui and Bi Gao tried to stop him, and finally he had to bring in Huo Guang.

When Liu Tan thought of Huo Guang's ability to nag people, he instantly became weak and had to let his subordinates try.

Different ratios will result in different glazes.

Of course, it may not have much to do with the ratio, and part of it depends on the firing temperature.

The first finished product was actually still rough, but the green bottle body already had the shadow of later celadon. He seemed to see the beautiful appearance of Ru kiln celadon through the light green.

Of course, this is most likely the result of Liu Tan's automatic beautification of his eyes, but it is undeniable that compared with primitive porcelain, ceramics fired at high temperatures have almost made a leap forward in development.

Liu Tan happily rewarded the craftsmen and asked them to continue working on their experiments, hoping that they could produce a set of exquisite celadon before New Year's Day. No, two sets, to be presented to the emperor and empress as gifts.

Although he brought a lot of things back this time, the New Year's gift and these two items still had to be separated.

Liu Tan was originally worried that there was nothing new on the gift list. Even if the gifts everyone gave were similar, as long as the value was there, it didn't matter if there was nothing new.

But he was used to coming up with something new and offering it to his superiors, so he felt a little uncomfortable when there was suddenly less.

Now that I have the celadon, I can finally get my job done.

When he walked out of the porcelain kiln, he was blown by the cold wind and felt dazed for a moment.

What was he originally going to do?

Oh, and make a toilet.

…

Didn’t we agree that there would be no by-products this time?