Originally, I thought that solid alcohol was made of methanol, but after trying to get it once, I found that it could also be made with ethanol with higher purity, but the flame was lighter when burning, so faint that you couldn't find it if you didn't look carefully.

With the trona produced in Qinghai Lake, chemical laboratories can finally synthesize simple products such as sodium hydroxide, also known as caustic soda. With caustic soda, soap is readily available. Then there is the higher purity of gasoline, diesel, glycerin, paraffin, asphalt.

With two alkalis, is the three acids still far away? The exact answer is far!

Because Hong Tao has only one person, there is no helper, at best he does some laboratory-level tests, and there is no hope of mass production, and it is even farther away from practical application.

Chemistry is not like metal smelting, the ancients originally would, but they were not refined, and after pointing out their shortcomings, explaining the direction, and providing them with technology, they would follow the right path or not.

But chemistry is different, and the ancients can be said to have no basis in chemistry. They may have some practice of chemical phenomena, but not a single chemical principle is clear.

The properties of every chemical reaction, every decomposition reaction, every salt, every base, and every acid are never touched by them, and all of them have to be learned little by little from scratch.

Therefore, it was relatively easy to popularize ironmaking, steelmaking, casting, and forging industries in ancient times, and if you want to develop the chemical industry, you can't start without ten years.

You have to start from scratch to teach a group of students, who not only have a foundation in mathematics and geometry, but also have a certain knowledge of physics, and then talk about chemistry.

The heavy snow did not weaken until dusk, how thick was it for most of the day? More than a foot!

Since he was basically resting during the day, Jiang Erlang decided to rush overnight. In this environment, sometimes it is more comfortable to walk than to stay where you are. As long as the food can keep up, it's best not to stop where you are, the more you sit, the colder it gets.

But walking on the snowy mountains at night is also a more desperate thing, and the line of sight is not a problem, the snow will reflect the limited moonlight, and it looks like the day in the polar regions.

The danger is the snow, some of which is soft, and you can cope with it with a snowboard. However, some snow has a hard shell, and it looks like snow is ice when stepped on, and it is very easy to slip.

There is only one possibility to slip on a ridge and fall down the snowy slope to your death. The specific soft and hard ones are not 100% sure even for the Tibetan people who have grown up here for generations.

At this time, the ice axe made by Hong Tao worked, and everyone took the ice axe in reverse and used the tail as a trekking pole to probe the hardness of the snow in front of them.

Even so, it is still not very safe, so Jiang Erlang according to the experience he gained from his usual training, a group of ten people, with a leather rope and a mountaineering hook to form a string, even if someone stumbles, it will not slide directly.

This method is called a lifeline by the special forces, and you can still climb the snowy mountain without stepping on a snowboard, but you are a little tired, but without a lifeline, it is troublesome, and it is easy to fall to death.

In the early morning of the next day, hundreds of special forces wearing white cloaks and stepping on two big feet arrived at their destination ahead of schedule. Thanks to the help of the snowboard, the speed of walking on the snow has doubled, and the physical consumption has decreased.

"The Xia people are really down, and they don't stop building cities in winter, these slaves are unlucky." The destination was the mountain peak on the north side of the valley of the Xia people's fortified city, and Hong Tao lay on the snow and looked down with a telescope.

The terrain is similar to that depicted by the Wasp, but the personnel have changed considerably. The number of troops and slaves who built the city increased here, and the camps stretched along the slopes on either side, and there were more than two hundred in a rough count. Even if there were 10 people sleeping in a tent, there would be more than 2,000 people.

Why is this changing? It's easy to see why. The main body of the city wall already has a rough outline, and if it can be completed in the winter, this large military fortress will be put into use in the spring of next year.

After another month or two of reserves, in the summer, the Western Xia army could use this as a supply station and barracks to launch a slightly larger attack on Huangzhou, dozens of miles away, which could catch the Song Dynasty by surprise.

Even if it can't occupy Huangzhou City, it will disrupt Qin Fenglu's troop deployment. Once the Song Dynasty transferred troops to Huangzhou, the states and counties on both sides would become empty, and whether they would find a suitable opportunity to attack should be the main reason why the Xia people built the city here.

They planned to have one more direction of attack to disperse the Song army's defenses. Every time there is more place to defend, the Song army has to arrange several times the strength of the Xia people, and the loss is much greater than that of the attacker, and it seems that the Xia people are becoming more and more able to fight a protracted war.

"My lord, I will have an idea...... "Lying next to Hong Tao, also holding a telescope, it was Jiang Erlang, he saw this city for the second time.

"To put it bluntly, it's almost dawn, we still have a lot of work to do, we have to hurry." Hong Tao had removed the telescope from the castle and was looking at the snow cover of the mountain below him, looking for a suitable blasting point.

"The last time I came to explore the way, I asked the people of the False Life Tribe, and they said that there was no valley suitable for building a city dozens of miles north from here. After crossing the big mountain beam in the distance, it should go all the way downhill, and then go further to Liangzhou. If you don't destroy this city and use it for your own use, you will not save dozens of miles of mountain roads when you go north in the future. It is not easy for the Xia people to recapture this city, the adult's hornet's nest is a weapon to defend the city, and this place is easy to defend and difficult to attack but cannot be gathered by a large army. Jiang Erlang pointed to the nearby mountains and rivers and put his thoughts out one by one.

“…… If there are 2,000 Xia troops to attack, how many people does Erlang think can be defended? ”

On military issues, Hong Tao is sometimes a mallet, and he can't see anything about the nearby mountains and rivers that are easy to defend and difficult to attack, which is a pot without basic military literacy. In addition, he didn't know the specific combat methods of the Xia people, so he had no way to judge at all.

"Three hundred people are enough, as long as there is enough food, grass and rockets in the city, the Xia people must withdraw if they can't attack for a long time. Wind and snow are raging in winter, flash floods are unpredictable in summer, and soldiers are available only in spring and autumn every year, both of which are less than January. ”

Jiang Erlang replied very affirmatively, he felt that the geographical location of this city was very good, and the distance from Huangzhou was not far, mainly because the climate caused the Xia people to be unable to use troops on a large scale and for a long time, and once they were frustrated in a short period of time, they had to retreat, and the cost of attack was very high.

"Oh, I understand why the Xia people have to spend so much effort to build a city here, if this place is occupied by the Xia people, it will be just as difficult for us to attack, right?" Let Jiang Erlang explain it in detail, Hong Tao's military literacy is rising.

"What your lord said is very ...... It's just that the last general can't think of how not to destroy the city and bury these Xia generals. Adults have always been resourceful, and there must be a way. "If you stay with Hong Tao for a long time, everyone will learn badly, Jiang Erlang, who was originally a little talker, will now be a sycophant, and his methods are still stable and ruthless.

"That's a must...... Don't steal the fun, I say you have to be able to do it. But you have to answer a question from this officer first, if you are the leader of the Xia army below, where should you take refuge after encountering an avalanche on the mountain to the west? ”

Hong Tao had already seen the surrounding terrain almost as well, and he had a plan when Jiang Erlang made his suggestion, and what he needed now was to predict the reaction of the opposing generals.

“…… It is safest to take refuge on the eastern slope of our mountain, which is a gentle slope separated by a mountain peak, and the snow on the western side will not rush over in any way. Jiang Erlang held the telescope and touched it left and right for a long time, and finally found the safest position.

"That's it, let's start with a scare snake, and then close the door and beat the dog. Whether this city can be kept depends on God's will, try? ”

Hong Tao also felt that this location was the best place to take refuge, but the avalanche was not something that could be completely controlled by manpower, and once the snow of thousands of years was blown up, it was impossible to calculate how large the avalanche would be, and it could only be relied on luck. Fortunately, no matter how big the avalanche is, it will not endanger the lives of these people, and if you lose, you will lose, it doesn't matter.

"Hey, hey, hey...... Try it, it's a must! Jiang Erlang smiled and learned Hong Tao's spoken language.