The graphite strokes are drawn on the jade paper, and the lines are thin, even, and very clear. There is no moisture and will not smudge the paper. The speed is beyond imagination.

Cen Hongmian had never seen someone use such a strange pen and hold the pen in such a strange posture to draw pictures. He was stunned and speechless.

It wasn't until Cen Xiyan picked up a milky white thing that he had never seen before and rubbed it back and forth on the jade paper that Cen Hongmian came back to his senses and couldn't help but curiously asked: "Sixth sister, what are you doing?"

What are you holding here?"

"Rubber." Cen Xiyan replied without raising his head or moving his hands.

"Eraser?" Cen Hongmian still said hello, and then asked: "What are you doing rubbing this on the paper?"

"Here." Cen Xiyan pointed Cen Hongmian to look at the drawing on the paper and explained: "Look here, I made a mistake in one stroke here. I can use another eraser and rub it to erase the wrong place.

"

Cen Hongmian carefully watched Cen Xiyan's movements of rubbing the artwork. Sure enough, where he had rubbed with the eraser, the lines had been rubbed away.

His eyes couldn't help but light up, and he asked like a child, "What is this thing made of?"

"Rubber, pumice powder, peanut oil, sulfur and other substances are mixed and heated." Cen Xiyan replied casually.

In the 21st century, there was no rubber in ancient China. The introduction and planting of rubber trees in China only lasted for more than a hundred years. However, in this time and space, rubber trees already existed in some tropical coastal areas. This discovery originally made Cen Xi

Yan was very pleasantly surprised!

Rubber has strong adhesion, insulation, and waterproof properties. It can be said that it has many uses for the group of technical house doors in Yuanyinmen.

Cen Hongmian was stunned for a second when he heard the formula casually reported by Cen Xiyan. Rubber? He had heard of it, but never seen it. It was a kind of tree found only in the southeastern coastal countries of Liguo.

Juice is not available in the Eastern Xun Kingdom, and almost only merchants have introduced it. Because it is of no use, I never thought that such a magical thing could be made?

"Pumice powder?" What is that? Cen Hongmian had never heard of it, so he couldn't help but ask.

"Oh..." Cen Xiyan then remembered that there was no such name at this time, so he explained: "It is a kind of volcanic rock left after a volcanic eruption."

"..." Cen Hongmian was silent for a while before holding back a sentence, "Sixth sister, you know so much..."

Rubber is something that is only available in Liguo. There are a few volcanoes in the eastern part of the country, but their locations are extremely remote. Cen Hongmian never expected that this sixth sister would be so knowledgeable, and those in the capital were quite talented.

Most of the noble ladies in the country know only poems and songs. I am afraid that none of the noble ladies understand these unorthodox things.

Cen Xiyan finally raised his head, glanced at Cen Hongmian, and then said lightly, "There are a few stewards in the shop who often travel around and have a broad vision. I heard some things from them and found them new, so I just remembered them.

.”

"Oh..." Cen Hongmian also glanced at Cen Xiyan. He didn't know whether he believed her words or not. Then he asked again: "Can this eraser erase the ink marks?"

"No." Cen Xiyan shook his head and said, "It can only be used to erase traces of graphite pens."

"Oh..." Cen Hongmian's eyes showed a hint of disappointment.

He saw that this eraser was very magical. If it could erase ink stains, he would like to promote its use. If it could only erase this kind of graphite pen, it would be of little use. With this graphite pen, the drawing lines are thin, even, and clear.

It's clean and a good thing, but if it's used for writing, it's too thin. The lines are evenly thick and won't look good, and the posture of holding the pen is so weird that it's hard to master.

However, this kind of graphite pen is useful to the craftsmen. Thinking of this, Cen Hongmian asked again: "Where did Sixth Sister buy this graphite pen? What's the price?"

As soon as Cen Xiyan heard Cen Hongmian's words, she knew what he was planning. However, she did not intend to popularize this kind of graphite pencil in this time and space.

Although the cost of this kind of pen is not high and it is simple to make, the time and space conditions are limited and modern processing machines cannot be made. If it is made purely by hand, Yuanyinmen does not have so many manpower and time to do it.

This kind of profit is small, has no technical content, and is still a consumable product.

In addition, in this time and space, graphite pencils are needed for drawing craftsmen. People are accustomed to using brushes for writing, and only the various fonts written with brushes, which are either flowing, delicate, or thick, are suitable for this time and space.

People may not be able to accept hard-pen writing according to the public's aesthetics, and it is not easy to preserve pencil-written words.

Furthermore, the cost of graphite pens is not high, but the hard-pen writing needs to be on paper with a slightly harder texture to be easy to use. Most craftsmen in this world should not have the conditions and luxury like the members of the Yuanyin Sect.

Use jade paper?

Therefore, Cen Xiyan said to Cen Hongmian: "This graphite pen was accidentally invented by a shopkeeper in my shop. It is not difficult to make and the materials are easy to find. If the craftsmen at home or in the Ministry of Industry want to use it, third brother, please tell me

The way they look at this pen, let them make it themselves and use it, but my sister would like to remind the third brother that graphite pens are hard and not easy to use on rice paper."

Cen Hongmian couldn't help but laugh after hearing Cen Xiyan's words, "Yes, not everyone can afford jade paper for drawing."

However, the craftsmen raised by the palace and the Ministry of Industry should be able to use it. If Prince Shuo and the Ninth Prince took this drawing and asked about the handwriting on it, he would answer it truthfully.

At this time, Cen Xiyan had already drawn several sketches. Then he picked up a ruler, compass and other objects, and began to carefully draw various partial sections, parts, proportions, sizes, etc., and various details.

Cen Hongmian was shocked again when he saw the ruler and compass used by Cen Xiyan! He had never known that there were such rules and regulations! It was so simple and convenient to use, and it was also small and exquisite! If Cen Xiyan hadn't used it to draw circles, squares would

, straight lines, etc., he is still wondering what these things are!

"Sixth sister, you have so many good things!" Cen Hongmian praised with bright eyes.

Cen Xiyan lowered his head to draw a picture and said calmly: "I just slightly improved these rules and regulations. Third brother, you have to know that lazy people have endless creativity for their own comfort and convenience."

The "rule" in the ancient people's mouth is actually the earliest prototype of the compass, a tool for drawing circles. The "moment" is the earliest triangular ruler, which is mostly used to draw right angles and squares. This is how the old saying "Without rules, there is no square circle" comes from.
Chapter completed!