It snowed heavily, and Chen Xu didn't go to work in the office of the Academy of Sciences, so he specially invited Zhang Cang to the mansion today, and the two of them sat on the kang at this time to study mathematical problems.

On the table is a box of colorful, pure crystals.

This box of crystal Zhao Qing gave him has been given to him for more than a year, but it has not been used.

In the era when there was no glass, transparent crystal could replace glass to make some optical equipment, such as convex lenses, and with a convex lens with better focus, you can try to make a telescope, but if you want to make a lens from crystal with the same hardness as glass, it can be said that it is not easier than steelmaking and ironmaking in the wild era of Daqin, and it is even more difficult to say that it is countless times.

There are no cutting tools, no grinding tools, no grinding and polishing tools, and no qualified geometric design tools.

In this era when there are no transparent standard triangles, compasses, protractors and vernier calipers, trying to design a lens that is enough to meet the optical standard is completely like looking at the stars, full of confusion, and completely unable to speak...... Take action!

Chen Xu turned over and over at the fist-sized chunk of pure and transparent colorless crystal stone in his hand, and couldn't help inhaling with a toothache.

Nima's, the plot in is all deceitful.

If there is no machine that depends on hand, it is estimated that it can be ground out for two or three years day and night.

Glass...... Glass......

, I'm a little stupid, now that I have coal and a crucible, I can try to burn the glass, as long as I can melt the crystal, and after melting, I can pour it into the mold like a bronze to cool, although this method may still not be successful, but at least it is much more convenient than polishing a crystal stone by hand.

"Dean Zhang, I may have a way to deal with crystals!" Chen Xu said excitedly.

Zhang Cang raised his head from the convex lens and concave lens structure diagram drawn by Chen Xu, and said in confusion: "Master Hou, I still haven't figured out the convex lens and concave lens you mentioned, why the light changes direction in it, and what is the role and significance of making it?" ”

"As I just said, if you make a convex lens, you can make a pair of telescopes, and if you do it successfully, you can easily see things that are miles or even tens of miles away, just like a person has a clairvoyant!"

"It's not that I don't believe it, but Hou Ye said that it's too unbelievable, the geometric formula you said can indeed solve the problem of measuring and calculating various shapes of earth, but from a distance, only fairy spells can do it, I think you should help me explain the problem of binary equations, so that I can write nine chapters of arithmetic faster!" Zhang Cang shook his head.

Chen Xu didn't bother to tell Zhang Cang.

Zhang Cang's mathematical knowledge is indeed good, but almost no one in Daqin is involved in the field of optical geometry now, only the Mo family will have some involvement, but that is also extremely superficial knowledge, the principle of light and shadow and the principle of small hole imaging described by Mozi are still 108,000 miles away from the lens, not to mention the telescope, and after the death of Mozi, the Mo family gradually collapsed, and the disciples of the Mo family are more inclined to some ideological changes, plus the Mo family has some religious colors, so the internal power struggle is also more powerful, Gradually, there is less and less research on physical theories.

But this incident is not that it cannot give him some intuitive enlightenment, it is the cold winter season, the glass is everywhere without ice, and the ice under the eaves is several feet long.

"Someone!" Chen Xu put down the crystal stone and shouted, and the two little maids hurriedly ran over.

"Go get me some thick ice, it's clean!"

"Yes, Master Hou!" After the two little maids saluted, Chen Xu also put on his shoes and went to find a knife, and after a while, the two little maids brought back a few pieces of ice with a clay pot.

Chen Xu squatted at the door, selected a piece of ice cube of suitable size from the clay pot, slowly cut it into a roughly convex lens style with a knife, then scraped the surface flat, and finally grabbed a few handfuls of snow to carefully rub the two sides smoothly, so the first real convex lens in human history was made.

Chen Xu's hands were red from the cold, and he walked into the room with this lens made of ice and said to Zhang Cang: "Dean Zhang is optimistic, look at the simplest effect of the convex lens!" ”

As Chen Xu spoke, he stretched out the ice cube in front of Zhang Cang and faced the geometric drawings drawn on the desk.

"Huh~" How the words and pictures have become bigger! Zhang Cang was amazed.

"This is the simplest amplification effect of a convex lens, which can make the object of observation larger!" Chen Xu handed the ice cube to Zhang Cang, and said while wiping his hands, "The principle of the convex lens is the principle of refraction of light in the ice, in fact, what we see is only a virtual image, and the real target is not magnified." ”

"Amazing, it's amazing!" Zhang Cang looked at the convex lens for a while, and then moved away to look, and even looked at the items in the room and outside the window, and his face was full of surprise.

"If we make two convex lenses overlapped, we can see things that the distant eye can't see by adjusting the distance between them!" Chen Xu said with a smile.

"Qinghehou's knowledge is really profound, this is really incredible, this convex lens can even see the veins on his hands clearly." Zhang Cang also lost interest in studying the equation, and began to study the fingerprints on his hand with a convex lens, and the two little maids who were startled couldn't help but run up to observe, and then ran out of the door to promote the new gadgets invented by Hou Ye.

"Hou Ye, Hou Ye~" Huang Fuque, the steward of the Hou Mansion, ran in breathlessly from outside, "Hou Ye is going to the door to greet him, His Royal Highness Fusu has come down!" ”

What is he here for? Chen Xu was inexplicable, but he still hurriedly put on his hat and went out.

"Your Highness, why did such a heavy snow come? Rest in the house! Chen Xu walked to the gate of the Qinghe Marquis Mansion, and Fusu had already gotten out of the car and was waiting in the snow.

"Qinghe Hou don't use more courtesy, my mother concubine is in poor health and can't eat and drink, and she can't sleep peacefully, my father heard that you made some food called bean sprouts, tofu milk and stinky tofu at home, so I specially asked you to come to the palace and bring some of these foods to my mother to taste, see if you can increase some appetite!" Fusu hurriedly saluted and said.

Belch! Chen Xu stayed for a while and said with a wry smile: "Your Highness, bean sprouts and tofu are okay to say, although the stinky tofu has a strong aroma, it smells very stinky, I'm afraid Concubine Zheng doesn't like it, and these foods are also difficult to get into the elegant hall, and these things are not suitable for eating in the palace!" ”

"Qinghe Hou is serious, my mother has not eaten well for several days, and if she continues to delay, I am afraid that her body will not be able to support it, so please Qinghe Hou go with me, Fusu is grateful!"

Well, Chen Xu returned to the mansion after reluctantly confessing, and instructed the kitchen helper to take a crockpot of tofu, a jar of edamame tofu, plus the prepared sauce and half a basket of bean sprouts, let a few kitchen workers take it and drive out of the house, and follow Fusu to the palace.

There is no queen in the palace of Qin Shi Huang, Concubine Zheng is the mother of the eldest prince Fusu, and she can be regarded as the master of the harem in terms of status, but Qin Shi Huang doesn't care about the women in the harem, there may be a few women he likes, but it is definitely not Concubine Zheng.

Therefore, he suddenly came to visit Concubine Zheng on a whim today, which also made the news spread rapidly among the many concubines in the palace, whether it was the concubines or the internal servants and officials of the Shaofu, they all secretly began to discuss.

After Chen Xu followed Fusu into the palace, he went directly to the imperial dining room first, and handed over the things he brought to the officials of the palace who were in charge of the palace meals for inspection.

It doesn't matter if the bean sprouts are the sprouts that grow from the beans, naturally there will be no problems, but the neat sprouts that grow so white and tender in the winter can only say that they are amazing after seeing them.

After being marinated in wine, salt, and spices, the tofu basically doesn't smell any strange, and even has an appetizing feeling.

As for edamame tofu, the taste is really not flattering, and when the jar is opened, the imperial chef who is ready to look good breathes directly, and then his feet are soft and he almost falls to his knees.

"Clear ...... Qinghe Hou, such as ...... How can you eat such a foul smell? A circle of people were crumbling with the smell of edamame exuding, and the Taiguan Ling covered his nose and stammered.

"After this thing is done, it smells stinky and tastes good, but I can't guarantee that Concubine Zheng will like it, so why don't you cover it up and get some bean sprouts and tofu!"

"That's great!" A circle of young officials and the imperial chef in the imperial dining room all nodded together.

"No, no, the fried stinky tofu is also requested by Qinghe Hou to send it over!" Fusu hurriedly said.

Since His Royal Highness the prince spoke, and the officials in the imperial dining room did not dare to dissuade him, Chen Xu naturally didn't care, put on the chef's apron, washed his hands, and personally fried a plate of bean sprouts with Qinghe tea oil, and then picked a few pieces of tofu and poured some Qinghe tea oil, and fried seven or eight pieces of stinky tofu for the palace maid to quickly send to Concubine Zheng's bedroom, Fusu also accompanied Chen Xu to go over, since he came to the palace, he still had to say hello to the emperor and Concubine Zheng anyway.

"It's cold, and I have to invite the Marquis of Qinghe to enter the palace, I'm uneasy!" Qin Shi Huang saw Chen Xu and personally greeted him at the door.

"Your Majesty and Concubine Zheng are so affectionate, so that Xu is envious, the family can eat together, it is a rare family happiness, if it spreads, the people of the world will have more respect for Your Majesty, family and everything is prosperous, Your Majesty is the Emperor of Great Qin, and every move is an example in the world!" Chen Xu slapped Qin Shi Huang with a few words of sycophancy.

"It's still Qinghe Hou who understands my thoughts!" Qin Shi Huang was a little impatient, but Chen Xu made him happy in a few words, as an emperor, he can not care about his own women's thoughts, but he has to care about the opinions of his courtiers and the people of the world, otherwise he will not repeatedly parade and show his merits everywhere, the purpose is naturally to hope that his achievements as the first emperor will be recognized by the people of the world.

And Chen Xu's seemingly casual words happened to hit Qin Shihuang's heart.