The students listened to Bai Ziyun talk about the truth of all things in the world, and their hearts were shocked and excited, and Bai Shangxian finally began to talk about the knowledge of the Immortal Dao.

Liu Bei's mood is the same, secretly celebrating that he is not as ignorant as those other senior brothers, and when he heard that Zheng Xuan, a member of the party, came to teach, he didn't want to study anymore. See what I'm hearing now? O power of God, the immortals want to teach us the knowledge of God.

In fact, this kid came to be a Taoist boy completely with an opportunistic mind. He knew that he didn't like his teacher Lu Zhi, and he couldn't help him in his career. Lu Zhi couldn't hold his thighs, so he came to hug Bai Ziyun's thighs. The one who has the same mind as him is his friend Jian Yong.

Liu Bei has always wanted to worship Bai Ziyun as a teacher like Gongsun Zhan, and he also asked his friend Gongsun Chan for help, but for some reason, Bai Ziyun never agreed. Liu Bei thinks that his intelligence is not worse than Gongsun Zhan, but the difference is just his family background. Later, when he saw that Bai Ziyun's apprentice was either a big family or a skilled person, he gave up the idea of apprenticeship.

Now he has finally entered the Confucian Academy founded by Bai Ziyun, but he is only a registered disciple, and he is 108,000 miles away from Gongsun Zhan's true disciple. Liu Bei is unhappy in his heart, but what can he do?

Bai Ziyun did not accept Liu Bei as an apprentice, because Liu Bei is not yet a climate, and he needs to be honed for a while, he is still quite expectant of this kid, expecting him to achieve something like in the original history.

“…… Hundreds of years ago, a king in the Western Regions gave a goldsmith a piece of pure gold and ordered him to make a very elaborate and ornate crown. After some time, the crown was made, but the king did not believe in the goldsmith's character. He suspected that the goldsmith might have infiltrated something else, so he called the goldsmith to inquire about it. The goldsmith flatly denied it, and vouched with his head that there was no fake, and weighed it in front of him, which was exactly the same weight as the original gold nugget. However, the king thought that perhaps the goldsmith had infiltrated the fake, for it was possible to make up the weight by mixing it with something else. Ladies and gentlemen, do you think this king is too suspicious? ”

Bai Ziyun looked at the schoolchildren with a smile, and the schoolchildren looked at each other, and they all felt that this king was too suspicious.

"Dean, is that goldsmith really fake?" Liu Bei couldn't help but ask.

Bai Ziyun smiled and said, "The king didn't trust the goldsmith, so he called a very famous local sage to tell if the crown had cut corners. When the sage returned, he thought about it repeatedly, but he could not come up with a good solution, because the solid gold nugget was different from the hollowed out crown, and it was impossible to calculate its volume without smashing the crown and casting it into a gold nugget, and therefore it was impossible to verify whether it was adulterated. He racked his brains and couldn't figure it out. ”

One day, he went to take a bath, and as soon as he lay down in the tub filled with warm water, the water overflowed and he felt his body rise slightly. Then it occurred to him that the amount of water discharged by objects of the same weight is also different due to the difference in volume...... He stopped bathing, jumped out of the tub and ran home from the street naked. He first placed the crown in a basin full of water and measured the overflowing water. Then he put the same weight of pure gold into a basin full of water, and measured the overflow again. As a result, he found that the second spill was less water than the first. So he concluded that the goldsmith had mixed the crown with silver. So the goldsmith was beheaded by the angry king. ”

The schoolchildren looked at each other, did this method really work? Is this sage of the Western Regions really so smart?

But the story was not over, and after a few years an old woman came to the sage, and the old woman took out a golden orb and asked the sage to help him test whether the gold had been stolen by someone else! After determining that there was no difference between the original total amount and the golden ball, the sage tested the volume using the previous drainage method, and found that according to his previous theory, the golden ball was miserably infused with other components! When the sage announced the results in public, the old woman was so angry that she turned the golden ball into two, and surprisingly, the golden ball was hollow! It turned out that the old woman was the mother of a craftsman whose head had been cut off by the king, and in order to prove her son's innocence, she spent years trying to prove the sage wrong. And it turned out to be exactly what she did, because the sage had neglected to make many of the countless gold ornaments in the crown hollow, and the result was that the sage's method of determining the volume of objects was not entirely accurate. ”

All the schoolchildren didn't expect such a result, and they all laughed at once, and their hearts were full of contempt for the sage who pretended to be smart.

"This story tells us not to trust authority too much, not to be too superstitious about someone's abilities, that king trusted the abilities of a sage too much, and ended up killing a man in vain. Perhaps the sage had never missed a lot of problems for the king before, but this time he was wrong. Since the pre-Qin period, there have been many kinds of immortal techniques, some of which are very reasonable, and some of them are preached by famous monks, and people who don't know the truth believe in these so-called immortal techniques, blindly cultivate, and as a result, they die. This kind of thing has happened many times in the last hundreds of years, and it is not convenient for me to talk about it here. When I say this story of the sage, on the one hand, it is to warn everyone not to blindly trust authority, but also from this story, it is said that there is a force in the world, and this power is called buoyancy......"

In this classic story of Archimedes, Bai Ziyun deliberately did not mention Archimedes' contributions, and said that his scandal was that some black people were Archimedes, but fortunately, he was not nominated, otherwise the reputation of the old man would be completely stinky in the East.

After Bai Ziyun finished the lecture, he went home, and as soon as he walked to the door, Xu Laojiang came to report the good news, saying that the two workshops of glass spinning and paper mill were finally done. Bai Ziyun was suddenly overjoyed, the two big killer weapons of glass and paper can finally be made.

The manufacture of glass needs to use quartz sand, soda ash and manganese ore, there are many such things in the Central Plains of quartz sand, this thing is shiny, very eye-catching, a little inquiry in Zhuo County found a quartz sand area, soda ash is also easy to make zuò, but the manganese ore is not easy to find.

It's not that there aren't many manganese ore in the Central Plains, but that no one in this era knows about this thing at all, and in the end, Bai Ziyun followed a few mountain farmers who were familiar with the mountains to run in the mountains for a few days, and finally found a manganese ore mine.

Under Bai Ziyun's guidance, the craftsmen made glass on the first day, and they quickly mastered making glass of various colors. This is the advantage of having a detailed secret recipe, unlike those who only understand the principle and need to explore it themselves.

After a few days, after the craftsmen have become familiar with the process of making glass, they use the pouring method to create a high-quality flat glass, which is then pasted with tin foil, then poured with mercury, and a mirror is made. Finally, the carpenter Lu Daniu made the mirror frame, and a mirror was completed.

Lu Daniu's carpentry skills are good, especially after cultivating internal skills, the techniques are more precise, and the vanity mirrors manufactured are exquisite.