.” Speaking of this, Qiu Dizhao couldn't help but complain. "In the past, when carving jade, the most feared thing was that the jade material was impure. At the critical moment, there were mixed things. Unexpectedly, glass was not as good as jade material, because there were miscellaneous materials or bubbles in the middle, I didn't know how much it was scrapped, otherwise I would have to waste so much effort!"

There is no way to do this. Now the process is at that level. Thicker glass is prone to impurities and bubbles, which will not be able to solve this problem for a while. Xu Ping tried his best to do his best to cast a rough blank with careful calculations, which greatly reduced the thickness of the glass and reduced the amount of grinding. Otherwise, Qiu Dizhao would have to spend more time.

Yan Su was more concerned about this matter than Xu Ping. After hearing Qiu Dizhao's words, he couldn't wait to say, "Since that's the case, Dizhao took a sip of tea and took a break, and we'll go over and see what?"

Facing the two waiting officials, Qiu Taizhao couldn't take up the airs, finished the tea in the cup, and stood up and said, "Since the two waiting officials are so anxious, let's go and see where there are unsatisfactory places."

"Okay, okay, wait for the imperial edict to go first!"

Yan Su hurriedly got up and went out of the living room with Xu Ping with Kaizhao Qiu.

When I arrived at the small room where Qiu Kaizhao worked next to me, the choking smell of dust came to me. Although it was ground with water, the dust all over the sky was still inevitable.

Xu Ping frowned. The working environment was really difficult. He thought to himself that after a few days, he would find a way to make some masks for these people so that they would not absorb dust all day long, which would be harmful to their health.

After entering the house, Qiu Daizhao carefully took a transparent lens from the table, polished it with the silk cloth placed next to it, and handed it over carefully, saying, "Please look at the official waiting to be in charge, do you like it?"

Yan Su took it, held it in his hand and tossed it over and over again, and then held it in front of him to look at it. The scenery seen through the lenses was deformed strangely, which made him feel particularly novel. However, it was the first time he saw this kind of strange thing, and he was unsure. After looking at it, he handed it to Xu Ping: "Xu Ping is ready to make it, do you think this thing can be used together?"

Xu Ping took it and saw that the lenses were crystal clear and transparent, without any impurities or bubbles, with excellent quality. He nodded: "It's great, without any flaws inside. However, Qiu Diezhao, have you ever tested the spotlight?"

"That's natural. The deputy envoy ordered, how could I dare not do what I did?" Qiu Taizhao said, pointing to a black box behind him, "The two officials who are waiting to do it themselves. But now the sun has set, and the measurement may not be accurate."

"It's enough to test the Attack. Why bother to do it again?" Xu Ping said, carefully putting the lenses in his hand on the table. "What other ones besides this one? Attack can clearly mark the distance and distance of the spotlight?"

The focal length of the lens is very important. If you don’t know what to do, you can only get it randomly if you install a telescope.

The black box was made by Xu Ping to measure the focal length. It can be installed on one side, and the other side can be moved, with a ruler below. The other two sides are blocked with wooden boards, and the other side is open to allow people to observe. When the sun is just right during the day, install the lens to be measured on it, slowly move the focus side, and use the ruler to read out the focal length of the lens when focusing.

Sunlight can be considered parallel light. Using this method, the measured focal length value can basically be used. If sunlight is not used, optical means are needed to create parallel light, which is too troublesome.

Qiu Diezhao pointed to several lenses on the table and said, "There are five or six in total. According to Deputy Envoy Xu's instructions, there are fewer convex lenses and more concave lenses. Let's see how to use them."

Xu Ping stepped forward and saw that there were six lenses, four convex lenses, and two concave lenses on the table. The focal length was carefully marked with a pen next to it, and the lenses were generally crystal clear. Not far away, there were a lot of scrapped lenses, which Qiu Dizhao obviously took a lot of effort. The main reason was that the quality of the glass was poor, and the glass formula with high light transmittance and high stability was still exploring.

Yan Su leaned up, looked at the lens and asked Xu Ping: "What kind of telescope should be made?"

Xu Ping picked up two lenses with convex and concave lenses from the table, roughly estimated the focal distance, held them in his hand, and said to Yan Su: "Let's go up and look out of the room, follow the lens."

"Oh, why did the things I saw suddenly become bigger!"

Yan Su took a look and then stepped back suddenly, staring at him and shouted.

Xu Ping put away the lens and said, "That's it, otherwise how could he see things in the distance?"

He asked Qiu Dizhao again: "Didn't the lens barrel I made a few days ago put it here? Take it for use."

Kaizhao Qiu ordered his apprentice to take over the lens barrel made by Xu Ping and hand it over to Xu Ping.

This is a long cylinder, the main body is made of brass and polished, divided into several sections, which is quite exquisite.

Xu Ping looked at the focal length of the lens in his hand, took off two sections of the lens barrel, and the rest happened to be used together, and then he installed the lens in. The big end was equipped with a convex lens and the small end was equipped with a concave lens.

After installing it and fixing it tightly, Xu Ping raised the lens barrel in his hand and looked into the distance.

At this time, the sun had completely set down the mountain, and only the afterglow of the sunset still painted the world, and the light was not too dark.

Looking south, various houses and buildings blocked their sight and could only raise them a little, just to see the south city tower in the distance. Several soldiers guarding the city walked around listlessly, and the little leader leaned his hands against the female wall, bored and napped.

Xu Ping suddenly remembered a question. He held this telescope and stood on the commanding heights in the city. For example, on the Xuande Gate Tower, you can directly see Da Nei to the north. Is this question big or small? The emperor's private life is absolutely not visible to others, let alone the security of the palace. The former Privy Councilor Zhang Qi's family approached the imperial city and once built a pavilion at home, which was higher than the wall of the imperial city. After Empress Dowager Liu lost power, this became a crime and was ordered to be demolished. With the telescope, is it that the height of the construction of the city still restricted?

Yan Su saw Xu Ping being so stunted that he was so itchy that he said to Xu Ping: "The deputy envoy has seen it, let me see it too."

Xu Ping put down the telescope, handed it to Yan Su, and smiled and said, "Yan Waijian looked at the Nanxun Gate Tower, see what those soldiers looked like, and then compare with Wanshengmen."

"Just, how can you see it so far? The capital is not a small county town below. The small city can see the city at a glance! Not to mention the Nanxun Gate Tower, you can see the willow trees by the Bian River are divine objects!"

Yan Su said as he put the telescope in his eyes.

"Ah, did you really see Nanxun Gate? That's really Nanxun Gate!" This time Yan Su didn't take the telescope away, and shouted while keeping looking. The novel thing Xu Wai-yi ordered was indeed magical.

...
Chapter completed!