Before coming, Li Hao calculated the purpose of the prince's killer, Comrade Li Gang, to find him.

There are only two central ideas. One of them is naturally that people are overly ill. Li Hao expressed his helplessness in this regard. He had too many things to do, and the identity of the prince's attendant can only give way to other identities.

The second one is probably related to telescopes. After all, the last time I only demonstrated it to the old man, it was a bit tricky. I think this old man should have thought about it.

The facts proved that Li Hao guessed right. Not long after entering Hongwenguan, it was as good as a gift. The old man took a cloth pocket from the old servant who was accompanying him, and after opening it, he took out an iron pipe with a much more refined shape, inlaid with gold foil.

This should be one of the two telescopes Li Hao sold to Li Er a few days ago. Unexpectedly, the old man could get one. It seems that no rule is better.

Just as I was thinking, I saw the old man weighing the telescope he had made with a lot of money and asked bluntly: "Young man, this thing should not be worth 500 coins, according to my understanding, right?"

Regarding the old killer... no, Li Hao smiled at Old Li Gang's honesty: "The old man is as wise as a torch, and the materials for this thing are indeed not worth it."

"Then why do you charge so much money?"

Facing the aggressive Li Gang, Li Hao was as hiding as an old dog, and said slowly: "The old man knows how expensive Qianliwang is, it does not care about its materials, but the truth contained in it.

The reason why Qianliwang can observe things in the distance is that one is that there is a convex lens and a concave lens on both ends, and the other is the distance between the two mirrors.

How to calculate the thickness of the convex mirror and how to calculate the distance between two mirrors requires a lot of calculations. Such calculations are the reason why Qianliwang is valuable.

It can be said that the reason why the boy sold this item for 500 cents is actually because of knowledge, not materials. You should always understand this way, right?"

"Well, what you said seems to make sense." Li Gang nodded, selling knowledge rather than materials. Such words of five hundred guan seemed reasonable, after all, knowledge is priceless.

After pausing, Li Gang continued: "You have said so much, can you tell me how you calculated it?"

Just talk about it, I hope this old man’s three views will not collapse.

Arranged Eunuch Chang to go out to get paper and pen, and Li Hao generously promoted the optics of junior high school physics to the Prince and Taishi.

Small hole imaging, refractive principle, the reason for convex lens concentration, the reason for astigmatism of concave lenses, trigonometric function... Except for the Pythagorean theorem and arc Li Gang understands a little, everything else is all about the duck listening to thunder and fog.

Li Chengqian was even more confused throughout the whole process. He only saw Li Hao's mouth open and close. As for what he was talking about... he only knew.

Li Hao was also helpless about this. He was already very restrained and had not said anything deeper.

Before he knew it, the sun rose to the top of his head and began to go west again. Li Gang finally walked out of the shock just now, rubbed his swelling temples, and bowed to Li Hao: "It turns out that it is better to meet you than to be famous. Li Shidu, I have misunderstood you before, so I misunderstood you today, in front of the prince!"

"Oh, I can't do it, I must not do it." Li Hao hurriedly flashed aside.

Just kidding, if an old man who is almost ninety years old apologizes to him, what if he is worshipped to death, will this be a long life?

"What can't be done? No learning is done, and those who are good at it are the masters." Li Gang was very stubborn and said with a stern face: "If you are just half a bucket of water, or you only know some tricks of bewitching, let alone let me apologize, even if you appear in front of me, I'm too lazy to look at you."

Li Hao smiled bitterly: "Yes, yes, the old man is right."

Li Gang's face, which had just been relieved, became stern again, and he taught a lesson: "It's good to reply to 'yes'. If you have too many, it will only make you feel impatient."

"Uh...yes!" Li Hao expressed helplessness about this and replied seriously: "Students have been taught."

Seeing Li Hao's attitude, Li Gang smiled satisfied: "Well, knowing mistakes can improve, and a child can teach you."

Li Hao breathed a sigh of relief when he could satisfy the old man. He was about to say a few humility, but Li Gang continued: "I am old and cannot urge the prince to do my homework from time to time. Dejian, I am going to recommend you to Your Majesty as the prince's junior teacher. What do you think?"

How? Not at all.

What if you are poisonous? How old is I? The prince’s young master, the second grade, is that I can do it?

Yesterday, someone from the founding county magistrate who was a fourth-ranked official yesterday was so jealous that he wanted to kill me, the prince's young master...

Li Hao was so scared that he almost cried, and waved his hands repeatedly and said, "Old man, you must not use it. Although the students are quite knowledgeable and have bad character, they are still young and are as close as brothers to the prince. How can they become the prince's young master? Why don't you urge each other and make progress together in the future? What do you think?"

Li Gang's mouth twitched, and I don't know if it was stimulated by Li Hao's words. He pondered for a while and said, "Your age is indeed a problem. I don't think about it."

That's right! Li Hao breathed a sigh of relief.

Li Chengqian looked at Li Hao in amazement. How can a person's face be so thick? You are a little knowledgeable. I admit that, but what the hell is that your character is not bad? Do you don't know what your reputation is like in Chang'an?

Half an hour later, finally dealing with the old Li Gang away, Li Hao sat down on the ground so tired, and breathed a long sigh: "Huh..., I finally left."

Eunuch Chang shouted with great gaze: "Oh, my uncle, why are you sitting on the ground? Get up quickly, it's cold on the ground. Come on, send me a brocade dock to my uncle."

Li Hao shivered by the sound of his little intestines and waved his hand and said, "Forget it, no need, I'll sit here."

After saying that, he stood up with the help of Eunuch Chang and sat on the table that Li Chengqian usually used to study.

Li Chengqian came to Li Hao with a wry smile, patted his shoulder and said, "Dejian, the teacher is straightforward. You can say whatever you think, don't take it to your heart."

"If I really go to my heart, I would have been scared to death." Li Hao rolled his eyes and said angrily: "Next time if there is such a thing, you will just say that I am sick and I am about to die of illness."

The Prince Young Master, it’s really a pity that the old man could think of it. Can he be a knowledgeable person? I don’t know how many pairs of eyes are staring at the Prince Young Master… I have to be beaten to death by a slaughter.
Chapter completed!