As the red glass cools down, it begins to solidify, and as the red fades, the glass slowly turns white and transparent.

Liu Jin held a pair of scissors in his hand to cut the glass at the joint, and then after the glass slowly cooled down, he also picked it up with pliers and began to observe it slowly and carefully.

"Yes, yes, I successfully fired the glass the first time, but the color of this glass is still not pure enough, and the color is yellowish, and it seems that we have to continue to experiment and find a way to get rid of this variegation."

"There are very few bubbles, and they are very small, if you stir more, stir, and raise the temperature a little more, you should be able to get rid of all the bubbles."

Looking at the glass ball that cooled down and condensed into a spherical glass, Liu Jin also nodded with satisfaction.

The first time the glass was fired, the requirements should not be too high, originally Liu Jin thought that it would be good to be able to burn the glass, but he didn't expect that the glass fired for the first time was already quite good in all aspects.

"This color is yellowish, it should be because there is some substance in the raw materials, I remember that in the history of glass in Europe, the glass of the first few hundred years was green glass, and everyone has always thought that this glass is green and cannot be changed."

"This green color is due to the fact that the glass contains a small amount of iron, and the iron reactants form divalent iron, and the compound of divalent iron makes the color of the glass green."

"Now this glass is yellowish, this should be related to the iron element in it, we must find a way to get rid of this."

Liu Jin carefully analyzed, this fired glass Liu Jin did not ask the system for help, because this point is not easy to come by, and it can be saved, and when there is really no way, Liu Jin will go to the system to ask for help.

"Brother Jin, this is Liuli?"

On the other side, Zhao Erhu, who was pulling the blower, also looked at the glass in Liu Jin's hand curiously, very curious.

"Well, it's called Liuli, but this thing is also a rare thing in our Daming, and it is very common in Europe, so it's nothing."

Liu Jin nodded, and then continued to take out some glass from the furnace, pour the glass into a special rectangular frame, and when it cooled, a piece of glass was formed.

"In the future, we must replace all the windows, the light in the room is too dim."

Seeing the glass made by himself, Liu Jin couldn't help but say, the windows of this era are so small and opaque that the room is very dark, even during the day, it feels gloomy, which once made Liu Jin very unaccustomed to it, and always felt too dark.

"Whew~Whew~"

Soon, Liu Jin also took out some glass again, took out a blow stick that had been prepared a long time ago, and began to blow the glass.

This glass blowing is a technical job, and it is obvious that Liu Jin, who blew glass for the first time, had a pain in his cheeks, and he didn't blow out anything decent.

"It's okay~ Fortunately, this is at least a glass, although it is ugly, but at least it can be used to drink tea, well, it must be kept, and it is also very good as a souvenir."

Liu Jin held the glass bottle he blew out in his hand, this bottle is very ugly, it must not be neat, let alone beautiful, but after all, it was blown out by himself, no matter how ugly it is, he likes it.

In the next few days, Liu Jin didn't go anywhere, concentrating on firing glass, constantly trying various methods, and the quality of the fired glass was getting better and better.

"Haha~ Colorless glass was finally fired, the quality of this glass is so good that you can't see a single bubble, and it can definitely be used to make telescopes."

Five days later, when the latest furnace of glass was fired, Liu Jin also laughed happily, after several days of repeated experiments and attempts, Liu Jin also finally made colorless glass.

"This glass is coated with a mixture of mercury and tin, that is the mirror, and this mirror can make money~"

Looking at the colorless and transparent glass, Liu Jin's eyes were full of small money.

You must know that in this era, even in Europe, where there is a lot of glass, mirrors are still very high-end things.

The first real mirror in history was in 1507 in Venice, Italy, a place famous for making glass, and the locals inadvertently smeared some metal liquid on the glass, which gave birth to the first glass mirror.

Its appearance caused a sensation throughout Europe at that time, becoming the new favorite of the princes and nobles, all of them rushed to spend a high price to buy a mirror, when the French queen got married, the king of Venice gave a very small glass mirror as a gift, which was a very precious gift, and its value was 150,000 francs at that time.

Because mirrors were so valuable, the Venetians even enacted strict laws to protect the method of making mirrors, and anyone who leaked the method of making mirrors was sentenced to death, and the place where the mirrors were produced was placed on a closed and isolated island.

Relying on this method, the Venetians kept the method of making mirrors secret for more than 150 years, and they did not know how much money they made by relying on the mirrors.

It is now the tenth year of Hongzhi, it is 1497 A.D., to be precise, although there is colorless glass in Europe now, but the glass mirror has not yet been invented, and it will take ten years for the glass mirror to appear.

Traditional mirrors are generally copper mirrors, although the clarity of copper mirrors is not bad, but compared with glass mirrors, it is too far behind, which is why glass mirrors are popular in Europe.

As European colonizers colonized the world, glass mirrors also spread to all parts of the world, and almost immediately became a thing that local princes and nobles rushed to buy.

Among other things, the Europeans did not know how much wealth they had plundered from all over the globe just by selling this glass mirror.

"Colorless transparent glass is a good thing, with you, not only can you make a small amount of money, but also can make telescopes, you can also make microscopes, many functions, for the study of natural science, especially cosmic astronomy, biological germology has extraordinary significance."

Liu Jin looked at the colorless transparent glass in his hand, and a smile appeared on his face, the astronomy and biomedicine of Europeans can be developed very rapidly in this era, which is definitely inseparable from this thing.

With colorless glass, it is possible to make telescopes, which are absolutely indispensable for cosmic astronomy, and microscopes can also be used to observe the microscopic world, which can greatly advance the development of biomedicine.