In the back office, Du Zhongxiao hugged his son, holding a small wooden stick in his hand, and taught him to blow soap bubbles. In front of him, there was a porcelain basin filled with blue water and a few pieces of iron. Next to her, Han Yueniang held a few pieces of caramel that had not been made for a long time, blew it gently, and handed one to her son when it was cold.

For thousands of years, sugar has been a luxury, with a small profit and a big profit. Jingxi Road is still too far north to grow sugarcane to squeeze sugar, and Du Zhongxiao didn't want to let go of this way to make money, so he hit the idea on starch sugar.

Caramel is one of the maltose, which has a long history and is sold on the market, and it is used to coax children to buy a small piece for a penny. The price of this sugar is not cheap, and adults rarely buy it to eat, and it is not common. And at this time, the process is not refined, either too sticky, or too hard, so it relies on a little sweetness to attract children. As for the candy blowers that can be seen almost everywhere in tourist attractions in later generations, Du Zhongxiao has not seen them.

The commerciality of this kind of caramelis is naturally not too good, and Du Zhongxiao has improved it according to the memory of his previous life. Select the sesame seeds from this place, fry them in a pot until they are cooked, grind them into powder, and stir them well with the melted syrup. When it cools, cut it into pieces with a knife and it becomes a simple halva. The sugar produced in this way is sweet and fragrant, and it is much more delicate than the caramel sold in the market. The most important thing is that after such processing, it is divided, which can be stored for a long time, convenient for long-distance transportation, and convenient for large-scale commercial production.

In recent days, Du Zhongxiao asked Shisanlang to bring a few people, continued trial production, and finally slowly matured. With black and white sesame seeds, two kinds of black and white halva are made respectively, a small piece and a small piece, wrapped in bamboo paper, which has the prototype of candy in later generations.

In the days of trial production, Du Zhongxiao's son had a large piece of gluttony, and he couldn't eat enough of this sweet and delicious halva. This sugar is not as sticky as caramel candy, one bite at a time, very convenient.

Children eating sugar are not good for their teeth, but there is no such concept at this time, Du Zhongxiao said it a few times, Han Yueniang didn't believe it, and her son gave it to him as soon as he wanted it, and Du Zhongxiao had no way to think about it. I had to wait for when the child had a toothache and then set rules for him.

Seeing that his son was still eating, Du Zhongxiao said to Han Yueniang: "If you eat too much sugar, your teeth will be eaten by insects, and sooner or later you will have to suffer." It's good to eat one or two pieces a day to satisfy your cravings, and you can't eat all the time. And the sesame seeds mixed in this sugar are too oily, and if you eat too much, you don't talk about eating, and you will have stomach trouble. ”

My son has eaten a lot of sugar these days, but it is true that he doesn't eat much, so Han Yueniang put away the rest of the sugar.

At this moment, Master Cui came forward and arched his hand: "Official, the new director Su Song has arrived at the yamen and is waiting outside. ”

Du Zhongxiao looked at the sky and said, "I won't do anything today, and the back office will set up a banquet in the evening to catch the wind for him." ”

After speaking, he handed his son to Han Yueniang, and Li Cui went to the front office together.

After Su Song left office from Yongcheng, he first went to Hangzhou to see his father, and then went up the Yangtze River, walked the Han River, entered the Tangbai River, and took a boat all the way here. Thousands of miles, in a hurry.

Du Zhongxiao came out, and the two sides saluted. Du Zhongxiao said: "Zirong came from afar to work hard, and went to the back office to rest. ”

When the two arrived at the back office, Han Yueniang had already returned to the residence with the child in her arms, leaving only the porcelain basin there.

Du Zhongxiao said: "I arranged a place for you to live over there, and I will take you there." By the way, why didn't Zirong's family come? ”

Su Song said: "The deadline is urgent, I will go first, and they will arrive in a few days." ”

The term of office of an official is calculated on a daily basis, with a term of two or three years, which refers to the date from the date of arrival to the date of departure. If you are transferred to several places during this period, then add up the number of days, and the date is enough to be considered full. If you ask for leave in the middle, you will have to deduct it.

Most officials are reluctant to go to remote areas to serve as officials, in addition to the difficult conditions, too much time wasted on the road is also one of the reasons. It can take months or even nearly a year to go back and forth, and if you move a few more times in the middle, the time is all wasted on the road. Normally, a term of office is three years, but the Sichuanxia and Guangzhou-Guangxi areas are two years a term, so they set aside one year to travel on the road. is also a ten-year official, unlucky, running around the road plus waiting to be elected, the term of office is only four or five years, and the gap with his colleagues is suddenly obvious. In this case, the benefits of being an official in the capital are revealed.

Su Song and Du Zhongxiao are in the same year, and the starting point of the two is about the same, but in six or seven years, the official position has been left far behind. It's okay to go to other places, to Du Zhongxiao, he traveled all the way, and it was good to arrive a day early.

arranged a place for Su Song, assigned an entourage, and the two went to the courtyard again, waiting for the dinner.

When they arrived at the place where they were sitting, the two sat down, and Du Zhongxiao looked at the porcelain basin on the ground, and the iron pieces in it had become much less.

Su Song saw it and asked, "What's in this?" Why is it here? ”

Du Zhongxiao said: "The water is full of bile alum, so it is blue. I put some pieces of iron in it to see if I could produce copper. ”

Su Song lowered his head and looked at it carefully for a while, and said, "The red on the iron sheet should be copper powder." Ge Hong's "Hug Puzi" cloud, with Zeng Qing coated with iron, 'iron is as red as copper', which should refer to this matter. But it's just a thin layer, and the iron inside is still iron. ”

Du Zhongxiao said: "Yes, the copper is just an outer layer, and when you scrape it off, the iron inside is still iron." However, if the copper covers the iron sheet, then take out the copper powder and scrape off the copper powder, and then put the iron sheet in it, and accumulate a lot, so that you can use iron to smelt copper. I'm going to give it a try today, and if this method works, it's much easier to smelt copper. ”

"Iron is cheap and copper is expensive, if this method is really feasible, it is a good way to smelt copper."

This is the wet copper smelting, which must be taught in chemistry classes, and is a great progress in China's copper smelting technology. Su Song is familiar with miscellaneous books, and he is no stranger to this phenomenon, and he doesn't think it's amazing. However, in this era, wet copper smelting has not yet been applied, and no one thinks in this direction.

At this time, the largest copper mine in the world is in Dexing County, Raozhou, where it is rainy, and the ore is dissolved in water, which becomes copper sulfate solution, which is actually bile alum solution. Du Zhongxiao replaced it with bile alum solution, which can basically simulate the situation there.

Iron is put into copper sulfate solution, and a displacement reaction occurs, which can replace copper metal. Although this method is scrap iron, it can be carried out at room temperature, which not only saves the fuel of pyrometallurgical copper smelting, but also greatly improves the production environment, and the cost is much lower.

A few days ago, iron ore was discovered in the mountains in the north, which aroused Du Zhongxiao's interest in chemistry, and this was the first thing that came to mind. As long as you know the principle, it is not difficult to understand this method, and it is easy to operate. The trial here is mature, and it can be reported to the imperial court as a political achievement of its own. Maybe when I will get a promotion opportunity because of this little invention. It is not easy to be promoted, and it is always good to have multiple paths.