The night of the eighth day.

Bi Fang's face illuminated by a flickering bonfire.

In the dirt pit on the side, there are two stripped squirrels.

As for the meat......

Bi Fang flipped over the two grills in front of him, one on the left and one on the right, both of them were very fat, and they had to be turned over from time to time to avoid grease dripping.

Animal fat is a good thing, and it can't be wasted at all.

The squirrel is charred on the outside and tender on the inside, but it's still not fully cooked, and there is a skewer of various insects on the side, and there is still the most important step before that.

Bi Fang picked up the bamboo tube on the side and carefully removed it from the campfire.

The bamboo tube is split in half, filled with water, and is bubbling and boiling, and in the middle of the boiling water, the pale yellow crystals rise into a "hill".

This is a "salt mountain".

The mineral salt that has just been extracted can be eaten, but it is not safe, first of all, there is the problem of bacteria, maybe Bi Fang scraped it off, it happened to be the white-limbed bison just licked?

Even if it's not a white-limbed bison, maybe there are other animals?

Even if you haven't licked it, the one in the batcave is not safe.

In addition, the ingredients in mineral salt are not only salt, but also many other impurities, although there is nothing wrong with eating a little, but it is definitely not okay to eat too much.

Therefore, Bi Fang still demonstrated the simplest way to minimize the risk.

He first dissolved the mineral salt in pure water, heated it with fire until the salt solution boiled, and then continued to heat until a large number of white crystals appeared in the vessel.

Boiling water, on the one hand, is sterilization, and on the other hand, it is the effect of temperature on solubility.

"The solubility of sodium chloride varies very little depending on the temperature, and the saturated solubility is about 36 grams at room temperature of 20 degrees; When heated to 90 degrees, it is only 39 grams. ”

"Typical impurities, such as potassium chloride and magnesium chloride, have a particularly pronounced change in solubility as the temperature increases. Taking magnesium chloride as an example, the saturated solubility is about 55 grams at room temperature of 20 degrees; When heated to 90 degrees, it has risen to 70 grams. ”

Bi Fang used a small spoon to dig out all the salt grains, and this was the third time he had precipitated salt.

Each time, he filled it with water, boiled it over a fierce fire, and steamed it for more than half an hour to extract enough salt.

"So when the solubility of sodium chloride in water reaches saturation, magnesium chloride is far from saturation, and as the water temperature increases, the difference in saturated solubility between the two is getting bigger and bigger."

"Eventually, in an aqueous solution heated to a certain high temperature, the magnesium chloride is still completely dissolved in the water as the water evaporates, and when the sodium chloride has crystallized and precipitated. It can be regarded as preliminary purification. ”

After stirring a little, Bi Fang put down the branch and said with a smile: "These are all the contents of junior high school chemistry, I think everyone should know about it, right?" ”

[Ah, yes, yes, yes, they all know, dog head]

[Have you learned, go around in circles]

[It's all back to the teacher]

[I'm a little impressed, but I've forgotten why I did it]

[Sure enough, if you learn mathematics, physics and chemistry well, you won't be afraid to go all over the world, and you may be able to take the college entrance examination with this ability]

[Am I here to learn?] Am I here to learn how to cook? What did I learn today? Three questions a day, three provinces of my body]

[Shrimp, and pork heart? 】

The salt is scraped off the container with a spoon, dissolved again in purified water, and finally poured into a container with activated charcoal, which is covered with large clean leaves and pierced with small holes.

Bi Fang explained: "Because there is no gauze, my charcoal particles are relatively large, so I don't agree to bring them out, of course, there may be some charcoal ash, but it doesn't matter, there is no problem with eating some charcoal." ”

"This filtration is mainly to adsorb impurities, and at the end of this step, the filtered brine is reheated to precipitate the salt, and it can be eaten."

When the salt crystals precipitated again, the squirrel happened to be roasted almost completely, and this time Bifang did not burn it, but roasted it to a dark yellow state.

The bamboo tube containing the salt water was taken down, and under the light of the fire, although it was not very clear, the audience could clearly feel that compared with the first mineral salt, this pile of salt was much whiter, but the particles were very large, which was very different from household salt.

In fact, the modern salt industry is a highly industrialized and standardized process.

People have an accurate understanding of the composition of coarse salt, and at the same time, a modern industry has developed on the basis of complete chemical basic research and the industrialization of salt production.

It is very difficult to "simply" purify the fine salt that appears at home in the wilderness.

The effort and effort wasted is not worth it, even if Bi Fang knows the process, he will not do it, and it is enough to get coarse salt that can be eaten for a long time.

Bi Fang carefully picked up a pinch of small mountain tips and sprinkled them evenly on the roasted squirrel, and the large grains of salt immediately melted into the flesh and bones and disappeared the moment they were combined with the hot oil.

An even more intense scent came to the nose, and Bi Fang tore the citronella into crumbs and gently waved it onto the skin, adding a unique lemon aroma to the scent.

Fanning the smell, Bi Fang took a sharp breath, and slowly spit it out after a long time.

"It's so fragrant!"

[I'm so hungry]

[It's nine o'clock, it's time for supper]

[Woo woo, squirrels are so cute, how can you eat squirrels, woo woo]

[Gluttonous, phew, gluttonous]

[Salt is the first of all flavors, envy]

His stomach was already growling, and Bi Fang couldn't wait to pick up the branch, bite off the bones and meat, and chew it heavily.

The abundant fat bursts in the mouth, accompanied by the salty and umami taste that has not been tasted for a long time, and the meat mixed with the slender bones is chewed into bone residue, except for the meat, which is a little old, so delicious that you can swallow it even on your tongue.

The two squirrels were eaten cleanly, and there were no bone residues left, and the insect skewers were also crispy and delicious.

After a full separation, Bi Fang bit the branch, brushed his teeth briefly, then took a bath with warm water, and then slept in a makeshift hammock.

The ninth day of survival in the Banna rainforest.

Bi Fang got up early in the morning, followed the direction sign in the forest, and hurried towards the campsite.

"If you do get lost in the forest, we can leave some clue signs to the people who may come to the rescue about what you have been to this place and which direction you are going."

"The mark of qualification must be able to let you see at a glance that this is artificial and contains a certain message."

"There are so many ways to do this. If you have stones, you can use them, but if you don't, you can use wood, grass, leaves, etc. to mark them. And it is best to use more than two ways together, which can increase the fault tolerance rate and avoid damage by animals or natural factors. ”

Stones, stones, sticks, tall grass can all be used as markers.

Bifang is to use stones and tall grass at the same time, stacking several fist-sized stones, plus tall grass knots, pressing in a certain direction, and determining the distance through the number of tall grass knots and bundles.

One is fifty meters, and if three are tied, it proves that the next sign is one hundred and fifty meters ahead.

"It's better not to use stones in the rainforest, because when it rains heavily, the stones may be washed away, and it's better to use stones larger than the size of a fist, by piling them up in different shapes, to determine the direction, and through the trees, to determine the distance, basically these two elements."

"In addition, another effective way to attract people during the day is to burn grass and leaves, and the smoke is a good indication of where you are.

At night. You can use the resources you have to start a large fire, and if you have enough fuel, you need to build three fires spaced out so that they are triangular in shape, each about 10 meters apart.

Of course, the premise of this is that you make sure that you don't start a forest fire, and if you do, you're almost 100% going to be buried in it. ”

Bi Fang chatted with the audience, chatting while hurrying on the road, and there were no accidents halfway.

It wasn't until noon that the familiar shed finally reappeared in front of everyone.

"Oh my God, it's finally here."

Bi Fang put the heavy bark frame on the ground, moved his sore shoulders, his forehead was full of hot sweat, and he ran for a morning, almost collapsed, and drank all the water.

All the tools I could throw were thrown away, and now I was covered with only a grass skirt, a wooden spear, a stone dagger, red mud powder, some materials, plus a few bamboo tubes and funnel bags, and finally a bark frame, which contained the iron bacteria that had been painstakingly collected, and a hat on it.

Even the clothes were thrown away because they were too heavy.

"I haven't been home for almost four days, let's not go in yet, the places I chose are all uphill, the rain is not easy to collect, there may be a lot of insects gathered here, smoke them away first."

Bi Fang plucked the inconspicuous yellow chrysanthemum around his waist, tied it with lemongrass and put it on the fire to light it.

"This is the pyrethrum I found on the road this morning, people will now deliberately cultivate it and use it to kill insects, because its head inflorescence contains 4 kinds of insecticidal components, including pyrethroid A, B and inthrivinin A and B, but they are all easy to hydrolyze and disappear, so don't let it touch the water."

[Wait, isn't this a chrysanthemum used to make tea?] 】

[Can this thing get rid of insects?] 】

[Damn, it's okay for people to eat, right? 】

[You can't touch water, so you can't touch fire]

"This is not a white chrysanthemum for making tea, it just looks about the same, and you usually can't touch it, this is an industrial pesticide that will be planted, and it is not common in the wild."

Bi Fang tossed the smoking pyrethrum into the shelter and waited for the smoke to spread.

"The pharmacological effect of insecticide is to paralyze the nerves of insects, and the effect is still very strong, and general insects can be revived within 24 hours after being paralyzed and drunk; After housefly poisoning, it is completely paralyzed within 10 minutes, and the mortality rate is about 60-70%"

"It is also toxic to arthropods, fish, amphibians and reptiles; However, it is not significantly toxic to birds and mammals. So we don't have to worry too much about what harm it will do to humanity. ”

The drone approached the ground near the shelter, and the audience could clearly see that some inconspicuous little insects were struggling to escape one after another.

Some of them were slow, and before they could even run out of the smoke range, their movements began to be sluggish, and they fell to the ground after a short time, motionless.

[, it's so poisonous! 】

[Can you kill mosquitoes?] It's been biting me to death for the past two days.]

[I also want to do it at my house]

About half an hour later, Bi Fang entered the shelter and trampled on the pyrethrum.

"There is no pyrethrum, we can also use pine needles, or sage, all have the same effect, but the waiting time is longer, and the effect of sealing the environment is better, at home, you can use this way to repel insects, pyrethrum or forget it, no matter what, it is poisonous."

After rummaging through the shelter that he hadn't returned for a long time, Bi Fang picked up a few stiff bugs that had been sucked and threw them out.

By the way, he swept away all the leaves that the wind blew in, but as soon as he swept away a leaf, a huge paw print attracted everyone's attention.