The graphite pen is drawn on the jade paper, the lines are thin and even, and very clear, there is no moisture, it will not smudge the paper, and the speed is even faster than you think.

Cen Hongmian had never seen anyone draw with such a strange pen and in such a strange posture of holding the pen, and he was dumbfounded and speechless.

It wasn't until Cen Xiyan picked up another piece of milky white that he had never seen before and rubbed it back and forth on the jade plate paper that Cen Hongmian came back to his senses, and couldn't help but ask curiously: "Sixth sister, what are you holding here?" ”

"Eraser." Cen Xiyan didn't raise his head, his hand didn't stop, and he replied in his mouth.

"Eraser?" Cen Hongmian still said hello with a face, and asked again: "What are you doing rubbing around on the paper with this?" ”

"Whoa." Cen Xiyan motioned to Cen Hongmian to look at the artwork on the paper and explained: "Look here, I have a wrong drawing here, use an eraser and wipe it, and you can erase the wrong place." ”

Cen Hongmian watched Cen Xiyan's action of rubbing the artwork carefully, and sure enough, where the eraser had been used, the lines had been rubbed off.

His eyes lit up, and he continued to ask, "What is this thing made of?" ”

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

In the 21st century, there was no rubber in ancient China, and the history of introducing and planting rubber trees in China was only more than 100 years, but in this time and space, some tropical coastal areas already had rubber trees.

The characteristics of strong rubber adhesion, insulation, and impermeability can be said to be of great use to the group of technical houses in the Yuanyin Gate.

Cen Hongmian was stunned again when he heard the formula casually reported by Cen Xiyan, rubber? He had heard of it, but he hadn't seen it, it was the sap of a tree that only existed in the Huili Country of the southeast coastal country, and the Dongxuan Country did not have it, and it was almost introduced by merchants, because it was useless, and he couldn't imagine that he could still make such a magical thing?

"Pumice powder?" So what's that? Cen Hongmian hadn't heard it, so he couldn't help but ask.

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

"......" Cen Hongmian was silent for a while before he held back a sentence, "Sixth sister, you know how ...... you are"

Rubber is something that only exists in Huili country, there are several volcanoes in the eastern part of the country, but the location is extremely remote, Cen Hongmian didn't expect that the knowledge of this sixth sister is so extensive, and those noble girls in the capital who have some talents know most of the things they know are just poetry and songs, I'm afraid that no noble girl understands these things that are out of the way.

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 from south to north, and have a broad horizon. ”

"Oh......" Cen Hongmian also glanced at Cen Xiyan, and he didn't know whether he believed her words or not, and then he asked again: "This eraser, may wipe off the ink?" ”

"I can't." Cen Xiyan shook his head and said, "It can only be used to erase the traces of the graphite pen." ”

"Oh......" Cen Hongmian showed a hint of disappointment in his eyes.

He saw that this eraser was very magical, if it could erase the ink, and he wanted to promote its use, if he could only erase this kind of graphite pen, it would not be of much use. This graphite pen, the drawing lines are thin and even, and clear and clean, it is a good thing, but if it is used for writing, it is too thin, the character lines are uniform and thick, and it will not look good, and the posture of holding the pen is so weird, it is not easy to master.

However, this kind of graphite pen can be used by craftsmen, thinking of this, Cen Hongmian asked again: "Where did the sixth sister buy this graphite pen?" How much does it cost? ”

As soon as Cen Xiyan heard Cen Hongmian's words, she knew what he was thinking, but she didn't plan to popularize this kind of graphite pencil in this time and space.

Although the cost of this pen is not high, the production is still simple, but, this time and space conditions are limited, can not make a modern processing machine, purely by hand, Yuan Yinmen does not have so many manpower and time, to do this kind of small profits, no technical content, or consumables.

In addition, in this time and space, it is necessary for the craftsman to use the graphite pencil, people are used to writing with a brush, and only the various or floating, or delicate, or thick fonts written by the brush are in line with the aesthetics of the public in this time and space, and the hard pen characters may not be acceptable, and the words written by the pencil are not easy to preserve.

And then there is, the cost of graphite pen is not high, but the hard pen is needed to be used on slightly hard paper, most craftsmen in this world, should not have the same conditions as the Yuan Yin Sect, the luxury of using jade paper, right?

Therefore, Cen Xiyan said to Cen Hongmian: "This graphite pen was invented by accident by a shopkeeper in my shop, it is not difficult to make, and the materials are easy to find. ”

Cen Hongmian listened to Cen Xiyan's words, and couldn't help laughing, "Yes, not everyone can afford to use jade paper to draw. ”

However, the craftsmen raised by the palace and the Ministry of Industry should be able to use it, if Prince Shuo and the Nine Emperor Princes took this drawing and asked about the handwriting on it, he answered truthfully.

At this time, Cen Xiyan had already drawn a few sketches, and then picked up rulers, compasses and other objects, and began to delicately draw various local sections, parts, proportions, dimensions, etc., and various details.

Cen Hongmian was stunned again when he saw the ruler and compass used by Cen Xiyan! He never knew that there were such rules and regulations! It's so easy and convenient to use, and it's so small! If it weren't for Cen Xiyan's use to draw circles, squares, straight lines, etc., he would still be wondering what these things were!

"Sixth sister, you really have a lot of good things!" Cen Hongmian praised with bright eyes.

Cen Xiyan lowered his head and drew a picture, and said lightly: "This rule and rules, I just improved it a little, third brother, you must know that lazy people are infinite in creativity for their own comfort and convenience." ”

The "rule" in the mouth of the ancients is actually the earliest prototype of the compass of the circle tool, and the "moment" is the earliest triangular ruler, which is mostly used to draw right angles and squares.

The history of the invention of rules and regulations can be traced back to the Xia Dynasty.