Reading lenses are not as strict as the lens requirements of telescopes. They have a large focal length and thin lenses. Relatively speaking, it is much easier to grind. Even if Qiu Diezhao's apprentice takes action, they have been polished out in large stacks.

Xu Ping took the lenses and carefully divided them into several piles.

These presbyop lenses are divided into three types, which correspond to different distances between reading, writing, painting and meeting guests, and the focal length of the spherical surface is slightly different. After all, the presupposed customer is a high-ranking official, and the more refined the better.

Picking up the pre-made copper lens frame, Xu Ping put three pairs of glasses in three types of lenses. He wanted to give it a try, but he didn't know that he felt dizzy just after a moment of looking. When he turned his head, he saw Yan Su looking at the sky with a look glass outside, and said loudly: "Yan is waiting to be made, you have to wait until the sky is completely dark at night. Come in, there are some things here. Come in and try it, there are different benefits!"

Yan Su reluctantly put away the telescope, held it tightly in her hand, and walked back to the living room.

Xu Ping handed over a pair of reading glasses and said, "Wear this mirror and try to see what's different about things."

Yan Su took it in his hand and looked over and over again, but he didn't know what to do, so he looked up at Xu Ping.

Xu Ping smiled and stepped forward, helped Yan Su put on his reading glasses, and signaled him to look around.

"Ah, Xu Waizhi, why are you so young? I always thought you had a black beard, why didn't you grow out yet? Ah, ah, suddenly, the things around you were so clear, just like you were twenty years younger!"

Could it be that in the eyes of these old ministers, he always had a similar appearance to Fan Zhongyan? Fan Zhongyan had a black beard. He was only thirty years old, so how could he have a beard?

Xu Ping shook his head repeatedly, feeling amused and crying. In the eyes of these bearded ministers, the officials under him only had a vague image and did not know the specific appearance? No wonder in the legendary novels I saw in the previous life, the big man was confused by people changing clothes at will.

Yan Su looked left and right with reading glasses for a while, and was amazed, and he would pick them off reluctantly, and kept saying, "This is a good thing, a good thing! He suddenly became younger when he put them on!"

"How about it compared to a telescope?"

After hearing Xu Ping's question, Yan Su held the telescope in his hand tightly: "Of course, it's more important to look at the sky. People are old and dizzy. Since ancient times, there is nothing in fact!"

Xu Ping smiled, ignored Yan Su, and said to Qiu Dizhao: "Do not know how to use your master, please put all the rest as you do in the three pairs of people. I will use it tomorrow."

Kaizhao Qiu agreed and brought his apprentice to the table with glasses.

Yan Su looked at him and couldn't help asking Xu Ping: "Why, Deputy Envoy Xu won't give me a pair?"

"Of course I will give it away. Yan Waijian is busy in the glass business. What's the point of just tying glasses! Besides, with these glasses Yan Waijian, I will see things clearly, and I will trouble you in a few days."

"Glasses? This is a good name. The mirror that is on your eyes can make you clear and upright." Yan Su nodded, "In fact, these things are all done by Deputy Envoy Xu. What can I help with? What will happen in a few days?"

"Although the lotus leak made by Yan Wai is excellent, it is quite inconvenient to use. I thought of a way to make a lighter and more practical clock leak, and I will also need Yan Wai helper."

The Lotus Leak is Yan Su's most proud masterpiece in his life. Before being recognized by Si Tianjian, he was an official outside and almost always built a simple version and placed it in the government offices in various places. This year, it officially became a national timing instrument in front of the Wende Hall, fulfilling his wish for many years. This is what he is most proud of. Xu Ping said that he would build more advanced timing instruments not only made him feel uncomfortable, but also couldn't suppress the strong curiosity deep in his heart.

After a while, Yan Su said, "If Xu Daoyi really has any good ideas, I will naturally have no choice but to do so!"

"Then I'm going to make a decision!" Xu Ping took advantage of the situation and quickly finalized it.

Making timing instruments such as clocks are not just physical and mechanical issues, but are related to astronomy. Because there is no unified timing system at this time, it is impossible to use your own clock and standard time to see whether it is accurate or not. You have to measure it yourself when calculating. Even if you have relevant knowledge and without the necessary tools and experience, it is difficult to accurately measure the time, let alone correct the accuracy of the time.

To know the accuracy of the table, you have to know the exact length of a day and a night first, and then divide it. Whether it is minutes and seconds, hours and titanium, you have to determine the time of twelve hours first. This is another function of Si Tianjian, which accurately determines the length of a day and a night and a year, and calculates the twenty-four solar terms from this.

Xu Ping can make a pendulum clock, but the timing scale requires the help of Si Tianjian. Of course, Yan Su, who spent half his life on the lotus leak, is a more suitable candidate. The error of the lotus leak can be controlled within one minute. This certainly requires a lot of structural ingenuity, but it is also essential to accurately measure the time of the day.

When the busy farming season passes, Xu Ping will have more free time. When he has time, he will have to do something from his previous life that he remembers. Making money is one aspect, and it is also convenient to live by himself.

It is very troublesome to not have convenient timing tools. For example, China has been able to accurately measure the year of the sun, but the calendar has always been based on the lunar calendar and mixed with the lunar calendar. Of course, there are many reasons for doing this, but one very important reason is that it can easily observe time. During the day, you can look at the sun to estimate the time, but the sun remains unchanged. At night, the moon has moon phases. People who are mainly lunar calendars, can only know the date and look at the moon in the sky at night to roughly estimate the time, and the solar calendar does not have this function. When portable timing tools such as pocket watches and watches become popular, the lunar calendar will lose a large part of its value, and the ancient lunar calendar will soon withdraw from life.

Like mirrors, clocks and watches are daily items that ordinary people need. They have a broad market and bright prospects, which can accumulate a lot of wealth for Sansi. These things that require a lot of skilled craftsmen are difficult to make in private, but for Sansi, especially with the help of Hanlin Academy, it is much easier.

What the new business is doing is daily necessities. After the production stabilizes, Xu Ping will gradually enter the luxury goods.

Seeing that it was getting dark, Xu Ping ordered Qiu Dizhao, his apprentices and others to do next, so he brought all the reading glasses and left the glass business with Yan Su.

Yan Su held the telescope tightly along the way, but he didn't care much about the reading glasses he gave him. He casually stuffed them into his arms. He kept urging Xu Ping, hoping to have a pair of wings on his back and go to find his old friend from Sitianjian, and take advantage of the sunny weather tonight and the cloudlessness, and go to see the vast starry sky together.

Over the years, generations of people who have observed the celestial phenomena have recorded countless star maps and attached many myths on it. Today, with the help of a telescope, the veil of the starry sky that cannot be seen clearly can be unveiled. Yan Su was very excited when he thought about it. To be continued.
Chapter completed!