After leaving Beijing, Han Gang and his entourage continued to transfer to stagecoaches in the post houses along the way and quickly went south.

It's only been two days, and I've already arrived in Ruzhou, which is very fast. It's just a little slower than last year and going south with Zhang Dun.

Traveling on the official road, there is a fixed number of distances to be walked in a day, and all of them are predetermined for one trip and one journey. Depart in the morning, and when twilight falls, you can stay in the reserved inn. If the itinerary is urgent, you can also travel at the same time. Generally, others are in a hurry, which is a two-way journey that can be completed in one day. The day before yesterday, when Han Gang and Zhang Dian went south, they walked seven miles in two days.

At that time, both Han Gang and Zhang Dian were a little unbearable, but the military situation was like fire, and they couldn't delay for a moment. In order to go south as soon as possible, I had to do that. Zhang Dian also said on the same day, "But after a year or two of sitting in the yamen, I don't realize that I have been resurrected." Han Gang also felt the same way, completely losing the ability to ride a horse and walk three hundred miles a day in Longyou.

However, this time the journey south was different, and after Han Gang walked around the south, he regained his old feeling and regained his adaptation to the long journey on horseback.

On this day, I also traveled all the way, and when it was getting late, I arrived at the junction of Ruzhou and Tangzhou, that is, the section of Fangcheng Mountain. Han Gang was originally going to rush to Fangcheng County in Tangzhou in one go, but when he looked back at the four staff members who followed him, they were all already sweating profusely, and they didn't even have the strength to sit up straight on their horses.

Han Gang stopped his horse in front of a small post station, "Let's get here today, I won't be able to catch up with Fangcheng County depending on the sky." ”

Listening to Han Gang's words, Li Fu and the four of them almost rolled off their horses, their legs shook straight, and they held on to the saddle and gasped for breath for a while.

The stagecoach on which the group was riding, although they had all changed in the middle of the delivery shop at noon, was also very tired, and the wheezing nose was spewing rough air, and the whole body was covered with sweat, and all the fur was wet.

Hearing the movement outside, the post man in the post station hurriedly greeted him. After asking Han Gang's identity, he saluted in a panic, and then hurriedly commanded his post guards to tidy up the room for Han Gang and them.

A veteran who looked to be fifty or sixty years old, acting as a post officer, came to lead the horse, and wiped it on the horse's back, and his hands were immediately covered with water marks. He tugged at the reins, pulled the horse to the manger behind, and muttered in a low voice: "This time, there will be no need to open for half a month." ”

Han Gang's ears were sharp, and he heard the post guard complaining. He was not angry, shook his head and said: "After all, it is not a post station in the northwest, there are few stagecoaches, and there is no one who is good." ”

Han Gang has memories from the afterlife, and he has traveled more than anyone else. But in this era, he has only experienced Kansai, Guangxi and the Central Plains, and has not been to the eastern coastal zone once.

Relatively speaking, Ma Zhu, the eldest, has much more experience in studying the world, and he also relieved himself a step earlier, and said with a smile: "The post station in western Beijing is quite good." Fujian raised on the island of the Zhou Yu horse, Longxue you can't recognize it as a horse, smaller than a donkey, but still put it in the post station to use. ”

"Shaanxi is now a tea and horse market, with nearly 30,000 Qingtang horses a year. The post stations in central Beijing, Shaanxi, and Hebei are more than enough, but they are almost in the southeast. Han Gang looked at Li Fu, Chen Zhen and Zhou Bi, who had not yet recovered their anger, "In the past two days, you have all been tired. After passing Fangcheng tomorrow and arriving at Luoqu Town, you can transfer to the official ship. If you sail day and night, it will not take many days to cross Xiangzhou, to Jiangling, through Dongting Lake, to Tanzhou, and then down to Xiangjiang River and Lingqu, and to Yongzhou. ”

Li Fusi's inner thighs have been worn badly by the saddle in the past two days, and their skin has been broken, and they have been enduring it. When I heard that I would be able to change ships tomorrow, I couldn't hide my joy on my face. It's just that Chen Zhen deliberately regretted and asked, "Won't you go to Fangcheng today?" ”

"Rest here today." Han Gang smiled, "You can also take a good look at Fang Chengsai, one of the nine fortresses in the world." ”

Li Fu raised his head, stood up straight, and looked left and right: "Where did the mountain come from?" ”

"It's true that I can't see it. However, this is indeed where Fangcheng Mountain is located. ”

Geographically speaking, this is from the pass on the northeast side of the Nanyang Basin. There is Tongbai Mountain in the east, and there is Bears Ears Mountain in the west, only the middle dozens of miles are empty. In the "Lü's Spring and Autumn Period", it is listed as one of the nine stops in the world, and it is called Jingcheng and Yanmen. But if you really want to talk about it, standing at the post station in the middle of the pass, looking to the east and west, there are no tall mountains, at most you can see shallow undulating low hills close to the horizon.

Not far from the door of the inn, there was a ravine more than ten zhang wide, but the water in it was so shallow that it didn't seem to reach even the knees, and there was no sign of flowing, and a violent foul smell could be smelled from afar.

"Is this the river?" Zhou Bi looked down into the ditch, "Why can't you see the water?" ”

"This is the Cao Canal that was prepared to communicate Jingxiang and the capital back then, but this section of Fangcheng Mountain is high, and the two diggings failed and failed to open the water. This section of the ditch is left here at the end of the year. Ma Zhu smiled at Han Gang and a few friends, "I went to Ezhou to visit friends two years ago, and I once walked on this road. ”

"If there is a channel to pass through this section of Fangcheng Mountain, then you don't need to go through the Bianhe River, you can go straight down to the south by waterway, and Jingxiang's grain doesn't need to detour to the Bianhe River." Chen Zhen said, "In the third year of Taiping Xingguo, in order to make Jinghu Cao Yun go straight to the capital, the Cao Canal was dug up. 'Nanyang goes down to the mouth of the weir, the backwater enters the stone pond, the sand river, and the Cai River reaches the Jingshi, in order to pass the water of Xiangtan. It's a pity that I can't see the results, otherwise the safety of the capital would not have to be entrusted to a Bianhe River. ”

Ma Zhu and Chen Zhen, these two Kansai people were able to tell the origin and usefulness of the abandoned canal in front of them, and no one was surprised. None of the disciples under Zhang Zai's door are nerds who can only read scriptures, water conservancy and river work is one of the most important government affairs in this era, as long as you have the heart to come out to do things, you must know a little bit.

Zhou Bi also seemed to be trying to show himself in front of Han Gang, and said not to be outdone: "The White River flows into the Han River, and the Han River flows into the Great River. The Shahe River flows into the Huaishui River and enters the capital by the Cai River. Communicate the water system of the two rivers and transport it to Beijing. If the Cao Canal is opened, you can take a boat from the capital to the south and go straight to Guizhou. ”

"It's a pity that the terrain is a little different. The first excavation was quickly washed away by a flash flood. Although the second excavation was successful, it took more than 100,000 soldiers and civilians to open up the channel, and the water depth at the bottom was only less than a foot," Chen Zhen pointed to the canal below, "In many places, there are only no feet, and the empty boat can barely be allowed to go." ”

"Although the Xianghan Caoqu failed to succeed twice, didn't it become a section?" Li Fu said that although he didn't know the ravines in front of him, he still had an in-depth understanding of the water conservancy canals in the country, "The canal that connects the Hanjiang River in Gangneung has been dug through." From Xiangzhou to the south of the Han River, you don't have to go all the way to Ezhou [Wuhan], you can directly transfer to Jiangling through the Jianghan Cao Canal, and you don't have to walk thousands of miles of waterway. ”

"The waterway is impassable, so it's useless to say anything." Ma Zhu sighed, intending to calm things down, "It's a pity." ”

Chen Zhen suddenly smiled and said: "The little brother doesn't dare to say anything about the geography of this place. But if it's just that the water is low and shallow, there are some workarounds. ”

"What's the solution?" Several people asked together.

"With the bucket door! On the Bianhe River, the bucket gate is used to adjust the water potential and release water to silt the fields. ”

"If it worked, it would have been used a long time ago." Zhou Bi shook his head, "Doumen can indeed adjust the water depth, but there is already living water in the Bianhe River, and the water in the Xianghan Cao Canal in front of you can only have no feet, and the Doumen is useless." ”

The four classmates were faintly competing with their knowledge, but Han Gang was happy to see it, and healthy competition was a good thing. And when they get to the office, they will naturally divide their labor. I'll keep their emotions under control.

He also looked at the ravine in front of him. When he went south that day, he also talked to Zhang Dian about the abandoned canal.

In fact, this is the passage of the South-to-North Water Diversion Project in later generations, and it should be the middle line. The famous boss of the Danjiangkou Reservoir, Han Gang still has some impressions. He remembers that the middle line of the South-to-North Water Diversion Project could flow to Beijing, and it was probably because of the dam of the Danjiangkou Reservoir that the water level was raised.

At the moment, of course, there will be no Danjiangkou reservoir, so it was opened twice and failed twice. For the first time, the stone weir at the head of the canal was washed away by heavy rain. The second time it did get through, but the water level was too shallow for boating.

As long as this section of the Cao Canal in Fangcheng Mountain can be opened, you can take the waterway from Yongzhou to Kaifeng, and you only need to change boats a few times in the middle - now you can actually do it, but that is to detour through the Yangtze River, enter the Bianhe River, and go out of the river for thousands of miles - and more importantly, Chen Zhen said that Kaifeng will not only have the Bianhe River as the lifeline of communication in the south.

However, the Fangcheng Pass seems to be gentle and low, but it is actually so high, which makes it difficult for the waterway to be smooth. However, in Han Gang's opinion, this section of the canal across Fangcheng Mountain is not unusable.

The water level in the channel is low and shallow, and this problem is also easy to solve. Dig deep into the bottom of the river and adjust the water level using weirs and locks, which in this case are called bucket gates. The facilities for adjusting the water level are available on the Bianhe River, and the 36 bucket gates in the Ling Canal have been used from the Qin Dynasty to the present.

But as Zhou Yu said, the ability of a single heavy doumen to adjust the water level is too small, and this section of the channel at Fangcheng Pass needs a higher water level, so it has to be abandoned. However, this problem can be completely solved as long as the weir can be used and multi-level locks can be used. There is a great hope of success in raising the water level in the canal through the weir and using multi-level locks to allow ships to pass through the weir. And it's really not good, there is also a track, as long as it turns around for dozens of miles in the middle, it is not troublesome.

But that's a later story, it's better to rest first, and how to calm down the cochin is the current problem to be dealt with.

After entering the post station together and having a simple dinner, Han Gang and the others slept in a room that was not comfortable, but clean.

It was only in the middle of the night that the sound of hooves startled Han Gang.

lifted the quilt and got out of bed, and heard a strong urging outside to urge the postman to change horses quickly.

Han Gang felt a little wrong. Running on the road at night must be an emergency military situation. At present, of course, Guangxi is the one who is at war in the south. And they went south from this road, and the war report in Guangxi naturally went north from here.

Han Gang put on his clothes and called the guards who were sleeping outside, "Go and ask which people are going to go." ”

The guards hurriedly went down, but in just a few moments, the soldiers had already changed horses and walked far. After the guards came back, they reported: "What Yi Cheng said is from Guangxi, but he doesn't know what is going on, and he doesn't dare to inquire, but he didn't see the soldiers with a dew cloth on them." ”