After discovering the suspected Zigong "Gongjing", Li Su and his entourage were stationed in the local area and carried out project rectification on the spot.

Li Su disliked the original name of the township Taitu, which was not pooping, and casually changed it, asking that the township be renamed "Gongjing Township", indicating that the official salt wells here will be directly under the direct jurisdiction of the salt officials of the Yizhou pastoral faction in the future.

Of course, Chen Shi has no objection, and let the county and the county's books be adjusted accordingly. The township elder Xu An also became the "Gongjing Township Elder", and immediately changed the brand of Fu Chuan (the township chief of one hundred stones does not have an official seal, only Fu Chuan).

The salt workers and craftsmen in the whole town were mobilized and mobilized, and the craftsmen from Jiangyang County also put into rectification and reform, and the construction process of "sealing gas pipelines" was in full swing.

Li Su didn't know technology, and he only knew in his mind that he would have to use a special sealant to achieve air tightness in later generations, so in terms of finding a way to make soil, he felt that it was better to let the craftsmen themselves tinker with it. Even if the craftsman fails, he can also provide Li Su with some lessons and let him adjust the direction of his efforts, he just needs to make sure that the scale of acceptance is well checked, and don't let the tofu scum project pass the test in confusion.

Four or five days passed, and several initial attempts failed.

The first method that the craftsmen came up with was to tie the bamboo cut directly with animal leather – something the county blacksmith came up with. Because the blacksmiths of the Han Dynasty had learned to composite sew with skin bags or materials such as pig bladders and tripe, and then tied to aerated bamboo tubes to blow air to the iron-making furnaces. They naturally feel that since they can blow air, they can seal the gas.

Unfortunately, the results of the experiment were not ideal, and when Li Su accepted the inspection, he strictly asked people to repeatedly ignite the outside of the seam of the bamboo tube, and occasionally it could still be ignited, indicating that there was a gas leak. The leather itself has a certain degree of airtightness, but the seams of leather and bamboo are not tightly tied, and the fit cannot reach the tightness of the airtight engineering level, and it is too dangerous to use it for a long time.

Chen Shi interceded with the craftsmen at the beginning, thinking that as long as there were seventy or eighty percent of the qi that could be transmitted to the stove, it didn't matter if two or three percent were leaked slightly.

But Li Su knows how big the risk of "gas leakage" is, and if there is a big accident, the death is not the most serious, the key is that it will cause the local people to fear the development and study of the use of natural gas? Maybe there will be a technological regression in the future.

"No! Absolutely not! Isn't it that we want to send some gas to the salt stove? The need is to make sure that almost all the gas is controllable! Li Su categorically refused.

After the blacksmiths' method of replacing the blast skin failed, the second one to come to the scene was the "direct mud seal to paste the fracture of the bamboo with mud" that the county masons came up with? Wouldn't it be surprising to think so? Because when the stove is built and the forging furnace is burned, it is also sealed in this way.

But Li Su is still very cautious? Let them do a pilot and continue to test to ensure that the safety effect can be implemented.

And Li Su instinctively rejects this approach? Because he thinks that the pipe will be built directly in the clay? In case it is difficult to overhaul and replace it in the future, it will have to be completely smashed. Moreover, the clay is easy to crack after a long time, and the durability of bamboo is not very good, and the life of the two materials is not the same? Replacing logistical difficulty is an absolute nightmare.

And? There was basically no porcelain in the Han Dynasty, only pottery, celadon and white porcelain, which were explored by the two Jin and Northern and Southern Dynasties, and matured in the Sui and Tang dynasties, which shows that the demand for kilns in the Han Dynasty was very low, and the airtight quality was difficult to satisfy Li Su.

After four or five more days? Sure enough, it still failed in the air leakage experiment, and the bamboo joint can actually be ignited on fire - in fact, you know that you think about it? How can plaster stuff be so airtight? Even waterproofing may not be able to do it, and the future generations will decorate the house? The bathroom also has to be specially made impermeable layer, indicating that natural mud or concrete? It is loose and leaky.

After three or four methods that have failed like this? Li Su also roughly summarized the airtightness characteristics of various materials in this era? Comparing the various materials with the characteristics of the airtight materials he had seen in later generations was a bit eyebrow-raising.

……

Another five days later, after many failures, Li Su personally adjusted his thinking, and the set of plans that seemed to have the best chance of success finally reached the sprint stage.

A group of overseers were like a great enemy, guiding on the spot, and even Taishou Chen Shi occasionally visited the factory.

"Hurry up, this time we must do it in strict accordance with the requirements of the governor, and no corners are allowed! This linen cloth is not dense enough, so I said, I want to find the most dense linen cloth as the base cloth. ”

"Brush the pigskin glue while it's hot, you won't put your hand in it and try to see if it's hot enough!" If it's too hot, it's not good for the linen to be tight, and it's too cold to stick tight. ”

"The bamboo tube is wrapped tightly, and the inner layers are all brushed with glue and wrapped tightly, and the outermost layer is brushed with raw lacquer. Stupid! Brushing raw paint is cooler than brushing pigskin glue, and it doesn't have to be so hot! ”

The craftsmen were busy carefully and compactly, and after several hours of rectification, they finally hammered out a test pipe that was more than 20 feet long.

This time, the sealing base they chose was linen, which was not favored at first - the linen itself was not airtight at all, it was too loose, and it was not even the best choice in the fabric category.

But because silk is more prone to aging and has a short lifespan, the most important thing is that silk is too smooth and lacks the friction to grasp the bamboo tube, so silk cannot be used.

Cotton cloth is denser and more frictional than linen. However, in the Han Dynasty, the white stacked flower (cotton) was only an ornamental plant, and cotton cloth was not popularized until the Southern Song Dynasty. In addition, Indian long-staple cotton is still in the country and has not been introduced, and the domestic white stacked flower varieties are not suitable for spinning and weaving, and can only be used as a warm filler, so the option of cotton cloth is not chosen before opening the road in Nanzhong.

If the base material is not good, use the auxiliary material to make up, the coating is viscous and dense enough, and you can still use the linen base to make airtight tape.

The excipients used by Li Su are two things: the natural gelatin boiled in pigskin has a binding effect, and the raw lacquer brush produced by the lacquer tree ensures air tightness in the outermost layer, and the double insurance should be enough.

The idea of this idea is actually backwards from modern materials - there are rubber, chemically synthesized airtight paint, and chemically synthesized superglue in later generations. Li Su can't do this, so he tries to choose pure natural substitutes that are close to its characteristics, which is a deduction that liberal arts students can easily think of naturally.

"Ignition!" With Li Su's order, the final plan also began to experiment in the production stage. The gas deliberately went a long way and lost 20 zhang away, and the end was also forked into several bamboo tubes, divided into several stoves to boil the brine in the big iron pot, in order to test the worst and most extreme situation.

After an hour and a half of fierce boiling, hundreds of catties of brine in each pot were boiled dry, leaving dozens of catties of salt. A rough calculation shows that the salt content of this brine is close to 10 percent, which is three times more dense than 3 to 4 percent of seawater.

The natural solubility of salt is only a few in three, so this is already very good. If you can dig out more than 500 meters of blackened shiny bitter brine, the highest mineral content can be close to 30%, almost reaching the natural limit, salty and bitter to death.

However, these are not the key, everyone is more concerned about whether there is an air leak.

Several salt workers stepped forward with torches, and smoked them with open flames at each bamboo tube interface a few inches away, and there was no remnant of open flames after taking away the torches.

"No air leaks! Finally no air leak! Was this a success? "All the accompanying officers were relieved.

"It's still Du Du Mingjian, I actually think of pig skin glue and lacquer, Du Du is really astronomical and geographical, and he knows everything."

"Don't worry, continue to cook for another three or five days to see, and use a torch every half day to test whether there is any air leak at the interface. It's all the time. "Li Su is very steady, and he did not directly declare success.

"You guys take a good look at it, and report it if there's a situation!" The county officials immediately instructed the merchants and salt workers of the salt works to serve well and not to make mistakes.

After a few days of trial cooking, the stability was finally confirmed, and Li Sucai ordered a celebration banquet, and then expanded production, and all the nearby wells that had a tendency to dig natural gas were renovated.

In this way, these wells that were originally not dug by salt workers can be further deepened, so that the output of gas and brine can be increased, and the quality of brine can be better.

However, from pilot to mass production, there must still be many small problems in the run-in period, not only technology, but also management and cost control.

For example, some management officials calculated the cost and felt that the raw paint brush of Nanzhong's specialty was too thick, so they wondered if they could reduce the number of paint layers-

The lacquer produced by the natural lacquer tree is a resin that flows out like cutting rubber, and the tropical mountains are the most suitable for cutting lacquer. The output of raw lacquer in Shudi is okay compared to other states, but it is still not as toxic as Nanzhong and the body. Usually, only a little amount of wood paint is used, and Li Su is used to make airtight coatings, which is more expensive.

Li Su of course was sternly opposed to attempts to cut corners in this regard, and the officials' suggestions were suppressed.

But the matter is not over, a few days after the start of construction, with the loss of materials too large and the progress is slow, after the salt official investigated, it was found that there were craftsmen who secretly drank gelatin boiled for construction, and also punished the craftsmen for this flogging and reprimanded the cost.

Li Su couldn't cry or laugh when he heard about this, but after thinking about it, he felt that it was normal - in ancient times, the paste pounded with pure grain was drunk by some people, not to mention the gelatin boiled in pure pig skin, which is a typical "edible gelatin", which can be directly produced in later generations QQ sugar and kitchen gelatin tablets.

When the craftsman confessed his guilt, he begged for mercy and complained, saying that he had never eaten such a clean and odorless pork skin in his life, and it was so delicious that he couldn't help it.

After Li Su heard about it, he personally ordered that stealing things should still be severely punished, but it was also necessary to improve the treatment of craftsmen and solve the sabotage in this area from the source.

So Li Su transferred a batch of pepper powder, plus Gongjing Township's original salt, and asked the cooks with the army to put heavy peppercorns to remove the fishy shame of the pork, and pickle and roast it with salt and pepper. In this way, most of the odor of the toilets-fed pigs of the Han Dynasty was masked and removed.

Because Gongjing Township wants to rebuild the fire well on a large scale, it takes a lot of pig skin to boil glue, so Taishou Chen Shi originally transferred a large number of pigs from various counties to slaughter and take skin, and there was a surplus of pork, so Li Su set the rules: all skilled craftsmen who have to transform Yanjing can eat two Han catties of skinless pepper and salt baked roast pork every day, and there is meat to eat, which fundamentally prevents the stealing of pig skin glue.

Later, this salt-and-pepper baked pig became the originator of salt dishes, and it has been improved and passed down from generation to generation.