Under Li Chengqian's pull, Kong Wen reluctantly dragged him out of the room, turned a few corners and came down from the upstairs, and ran to the carriage that came and came.

"Gao Ming, what are you going to do? Run a little slower. While running, Li Chengqian stumbled several times and almost fell, and finally Kong Wen had to stop him, and at the same time slowed down his pace, slowing him down.

"Come with me, you'll know when you get there." When he came to the side of the carriage, Li Chengqian opened the door to let Kong Wen get into the car, and urged urgently.

Kong Wen was confused by him, and at the same time thought of the dowry that Li Chengqian said in the room just now, she couldn't help but be even more flustered, and she didn't know whether she should get in the car.

"Little Ancestor, you hurry up, it's too late for a while." Li Chengqian urged again, there are still several places to run for a while, continue to grind, it is estimated that the time will really be too late.

In desperation, Kong Wen half-pushed and half-got into the carriage, and then the car drove out of Chang'an City under Li Chengqian's instructions and headed towards the glass workshop outside the city.

"Gao Ming, what are you doing in the glass workshop?" Knowing the destination, Kong Wen was even more confused and asked curiously.

After such a long time, her mood has calmed down, and she has put aside the so-called dowry, Li Chengqian is usually unreliable too many times, and there is no need to take his words seriously.

"Did your grandfather always feel that he couldn't see things clearly? I always like to squint my eyes and hold the book far away when I read it, right? Sitting in the carriage, Li Chengqian gasped, looked at Kong Wen beside him and asked.

"yes, how do you know?" Kong Wen nodded.

"Of course I know that almost all of the old guys in the court are like that." Li Chengqian pretended to be profound, until Kong Wen pursed his mouth, and then smiled faintly: "This is called presbyopia, and most people will basically do this when they are old." ”

"Is it a disease?" Kong Wen listened to Li Chengqian's explanation and was a little nervous.

"It's not a disease, it's just an inevitability when people get old, just like people have gray hair when they get older." Li Chengqian comforted Kong Wen.

"Then ......" Li Chengqian suddenly mentioned the problem of his eyes, Kong Wen faintly felt that this time out of the city should be related to the eyes of the old man at home, but he couldn't think of what the relationship was, and he wanted to ask but didn't know where to ask.

"Remember what I told you about muscle conditioning some time ago, right?" Looking at Kong Wen's curious eyes, Li Chengqian said: "There are also such muscles in people's eyes, and we usually adjust our vision through the retraction of these muscles, so that we can easily see things far or near. ”

"But when people get older, the muscles in the eyes will slowly lose some of their adjustment function, and then the near things will become blurry, which is the case of presbyopia."

Li Chengqian didn't know how to explain the imaging principle to Kong Wen, so he could only simply outline what presbyopia was through eye muscle adjustment.

"Gao Ming, you can cure presbyopia, right?" After listening to the explanation about presbyopia, Kong Wen's eyes lit up.

Li Chengqian is not a person who has no purpose, he can spend so much effort to explain the cause of presbyopia, so this trip must be related to this.

"yes, that's what it means to fix it." Li Chengqian nodded confidently: "Human muscles can't be adjusted automatically, so we use external forces to adjust." ”

"That magnifying glass of yours is the most crucial point of this, so now we are going to go to the glass workshop, get more magnifying glasses, and use them to test to see if we can achieve the purpose of correcting the etiquette."

Along the way, Li Chengqian and Kong Wen chatted about some simple imaging principles, and felt that it didn't take much time to arrive at the glass workshop.

"Adam, how many newly machined convex lenses are there?" Jumping out of the carriage and facing the bearded man who came out of the workshop, Li Chengqian asked.

"Dear master, there are one hundred and thirty-six pieces in total." Adam has been taught a few times by Li Chengqian, and now he is no longer as long-winded as before, and his speech is much simpler.

"Bring them to me, I'll be useful."

"All, all of them? Master, then, isn't the telescope out of production? A hint of surprise flashed across Adam's face.

It took months to get these 136 convex lenses, and they were all 'perfect' in terms of transmittance and bubble content.

"That thing will be produced slowly in the future, and now bring all those lenses, this palace will be of great use." Binoculars, Datang doesn't fight big battles now, it doesn't need much, and it's nothing to slow down.

"Yes!" As the largest boss of the glass workshop, Li Chengqian's words were unconditionally implemented, and soon a large number of convex lenses were packed in boxes and brought over.

"Adam!" Before leaving, Li Chengqian poked his head out of the carriage and said to the bearded man: "Get another batch of convex lenses, this time they will be larger, ten centimeters in diameter, one to five times, and five pieces of each." ”

"Yes, villain understands!" Although Adam did not know what this 'great' master wanted to do, he had already learned to ask less, talk less, and do more, so although he was very curious, he still agreed to do what he said.

"Go to the prison!" After leaving the glass workshop, after giving an order to the guards who were driving, he took out the convex lenses and compared them one by one.

It is true that reading glasses are convex lenses, but the degree of dazzle is different for everyone, and the power of reading glasses required is naturally different.

But fortunately, reading glasses do not have the same strict power requirements as myopia glasses, so as long as you can see more or less clearly.

Kong Wen didn't know this, but she was also very curious when she saw Li Chengqian picking around, and couldn't help but start helping under Li Chengqian's guidance.

However, Li Chengqian soon found that what he was doing now was in vain, because none of them in their group had presbyopia, so there was no way to determine that the lenses were suitable.

There is no way, in this situation, if you want to determine what kind of lenses are suitable for presbyopia, you can only find another way to find an old man to try it for yourself.

So, under Li Chengqian's prodding, Kong Wen sacrificed her grandfather and brought Li Chengqian back to the Kong family mansion in Chang'an.

"The old minister has seen His Royal Highness the Prince!"

"Brother Li Chengqian has seen Master Confucius!"

When I arrived at Kong's house, I naturally had to greet each other, and it was already tea time when the two sides were seated.

After taking his seat, Old Man Kong looked at his granddaughter and then at Li Chengqian, secretly sighed in his heart, and asked after a moment of silence: "His Royal Highness the Prince, I don't know what is the important thing to come here today?" ”

(End of chapter)