After the whole sect traveled to ancient times, I led the rebellion

Cheng Yu handed a few pieces of polished glass to Mu Qing.

It took him several days just to polish these pieces of glass.

Mu Qing walked over from the table.

She held the clear lens to her eyes and compared them.

"It's done!"

Mu Qing looked at the piece of glass in his hand with great joy.

Cheng Yu looked at Mu Qing tiredly.

"It can only be polished to this extent now."

He was somewhat dissatisfied with the glass pieces that had been polished over the past few days.

"Is this the concave lens mentioned in the textbook?"

"Ah."

Mu Qing nodded.

A convex lens, also known as a converging lens, is characterized by being thicker in the center and thinner at the edges.

This design causes light to refract as it passes through the lens, thereby converging the light.

Mu Qing picked up the lens and placed it in front of his eyes.

When a normal person wears a convex lens, the image of the object will fall in front of the retina, which is equivalent to becoming nearsighted, so he can only see nearby objects but not distant objects.

The adult fish waved his hands:

"You can't see anything clearly through this thing."

Cheng Yu thought of the time when he put the polished glass in front of his eyes. His vision became blurred and he couldn't see the scene clearly. He even felt a little dizzy.

"It's okay if you can't see clearly."

Mu Qing took the pair of lenses, the degree of which was very low.

Thinking of this, Mu Qing couldn't wait to verify his guess.

"Let's go to the agricultural base."

After Mu Qing finished speaking, he took the lens and ran away.

Cheng Yu saw Mu Qing leave quickly and went to the agricultural base.

So he followed reluctantly.

"Master Xu!"

Mu Qing leaned against the wooden door and looked at Master Xu who had returned to farming at the agricultural base.

Mr. Xu is trying to cultivate seedless watermelons.

He glanced at the textbook.

Watermelon is a diploid plant and needs to be cultivated into a triploid plant.

Alas, it’s a bit difficult.

Master Xu sighed and held the notebook in his hand farther away to look at it.

Colchicine can be extracted.

He was writing and drawing in a notebook.

When Mu Qing shouted, Master Xu's hand stopped writing:

"Mu Qing."

Master Xu walked briskly to Mu Qing:

"Colchicine must be extracted from daylily or autumn daffodil. I haven't researched the alcohol yet."

Mr. Xu felt a little lonely when he thought that it was still winter and there were no day lilies.

"Don't worry, don't worry. We can research seedless watermelons later. We'll sell them to the rich and powerful at a high price anyway. There's still time."

Mu Qing pulled Master Xu's sleeve.

"Master Xu, try this."

"Liu Li?"

"Yeah, to be precise, this should be considered glass."

Mu Qing demonstrated by fixing the two lenses in front of Master Xu's eyes with his hands.

Master Xu couldn't figure out what Mu Qing was thinking, and he was about to lower his head.

Just like that, he bowed his head.

Master Xu was surprised to find that he could see the words on the paper clearly without holding it far away.

The scene before his eyes was no longer blurry. Master Xu was amazed as he looked through the lens to see the long-lost clear world.

Seeing Master Xu's surprised expression, Mu Qing smiled and removed the lens from in front of Master Xu's eyes.

"These are reading glasses made of glass by adult fish."

Mu Qing had previously used simple equipment to roughly measure the range of Master Xu's degree.

This pair of reading glasses was specially made for Master Xu.

Mu Qing handed the lens to Master Xu.

"Strange, this colored glass is of high quality. When I put it in front of my eyes, I can see things very clearly."

The adult fish's eyes fell on Master Xu and then returned to the two pieces of glass he was polishing.

He remembered that he used it to see things, but it was not clear.

The adult fish silently expressed his inner doubts.

Mu Qing temporarily took back the lens from Master Xu's hand. Master Xu looked at the glass in Mu Qing's hand reluctantly.

This was the first time in all these years that he could see nearby objects clearly. The last time he could see clearly was twenty years ago.

As people get older, their eyesight becomes blurry. Like most elderly people, Mr. Xu suffers from presbyopia.

Master Xu couldn't help being excited when he experienced the vision he had in his youth again.

Mu Qing had thought about making a convex lens since he heard the farmer's disciples talk about Master Xu's blurred vision.

In response to Cheng Yu's question, Mu Qing took out a physics textbook from somewhere, pointed at the words on it and read them sentence by sentence.

“Convex lenses are widely used in optical instruments such as cameras, telescopes, and microscopes to focus and magnify images;

Concave lenses are mainly used to correct myopia and help people restore clear vision. "

"what."

Cheng Yu looked at the physics textbook with a confused look on his face. He was still learning basic mathematics and had thrown the physics materials aside. He only remembered the terms convex lens and concave lens.

As soon as Mu Qing saw Cheng Yu's expression, he knew that this guy didn't study well with Xu Yu.

There is still a long way to go in cultivating physical talents.

Convex lenses and concave lenses are completely two different objects.

Reading glasses made of convex lenses are only suitable for people with presbyopia. Basically, people as old as Mr. Xu are more likely to have presbyopia.

The adult fish is still young. If it can still see clearly even with reading glasses, Mu Qing would doubt the health of the adult fish.

According to the way Cheng Yu, a disciple of the Mohist school, or a candidate for the imperial examination, uses his eyes like this, even if he has poor eyesight, it should be myopia rather than presbyopia.

Mu Qing glanced at the adult fish.

However, it is hard to say. In China in the 21st century, presbyopia is gradually becoming younger.

Mu Qing made a brief trip to the agricultural base and took the opportunity to let Master Xu briefly experience the feeling of wearing reading glasses.

This lens is made of glass.

Most lenses in the 21st century are made of resin, which is lighter.

Mu Qing doesn't have any better materials right now.

The main component of glass is silicate, while the composition of colored glaze is more complex. In addition to silicate, it also contains various elements such as lead oxide, barium oxide, and zinc oxide.

The colored glaze that Mu Qing had made before was called colored glaze, but in fact it was almost like glass.

Otherwise it wouldn't be so transparent.

But she never told anyone the difference.

Reading glasses made of glass are heavy, so Mu Qing plans to give this pair of reading glasses to Master Xu. Since the degree is almost right, he can just buy a frame and use it.

Given Mr. Xu's scientific research madness, Mu Qing had to remind him not to wear his reading glasses for a long time.

Cheng Yu curiously took the glasses drawing that Mu Qing had drawn.

Mu Qing's painting skills tend to be realistic. Before his parents passed away, Mu Qing had always taken private lessons in the sketching class.

It is not too difficult to use the old painting techniques to copy the pictures in the mind and mechanical drawings in proportion.

Cheng Yu thought about what Mu Qing had told him about the concave lens, and quickly opened the textbook.