Starting from Robinson Crusoe-Chapter 221 - 100: Unexpected Gains (Part 2)

To be safe, after closing the backpack, he still took out the long-handled axe he carried with him, holding the axe in one hand and a lamp in the other, leading Lai Fu through the narrow cave passage.

The lamplight dispelled the darkness, and the number of pigeon nests ahead was gradually dwindling, and the path was getting narrower and narrower, as if it was about to close into a seam, blocking the way.

With the spirit of exploration, Chen Zhou put down his climbing bag, reduced his own width, and slightly turned his body to continue forward.

Squeezing through a rock crevice that could barely accommodate one person, and moving another dozen meters forward, the passage became increasingly spacious, allowing Chen Zhou to understand the internal structure of the cave.

It turned out to be a gourd-shaped cave, narrow on the outside and wide on the inside, and when reaching the depths of the cave, it suddenly opened up. 𝘧𝓇ℯ𝑒𝓌𝑒𝑏𝓃𝘰𝘷𝘦𝘭.𝒸ℴ𝓂

At this moment, the terrain underfoot began to extend downward, and the dim oil lamp could only illuminate the surroundings for three or four meters, with the high parts of the deep cave completely shrouded in darkness.

From a distance, the faint sound of water could be heard along with a cool breeze occasionally brushing his face.

Having read many tomb raiding novels, Chen Zhou felt as if he were a Tomb Raider Captain, venturing into an imperial tomb hidden in some geomantic treasure land.

It was deep in the night, and walking through the cave with Lai Fu, his vision severely obstructed, the atmosphere was rather terrifying.

The high parts were invisible, and the surroundings suddenly became exceptionally spacious, worried that there might be a broken cliff or other dangers ahead, Chen Zhou slowed his pace, trying to use the oil lamp in his hand to illuminate everything beside him.

As he walked, he found the ground becoming increasingly damp.

And on the rock wall he had been leaning against, besides the black-gray rock, there was a layer of mineral resembling large chunks of salt.

Chen Zhou, who had read many different farming novels in his free time, felt a sense of familiarity with this mineral, so he squatted beside the rock wall and pondered for a while.

Although he usually adhered to the principle of "a good memory is not as good as a bad pen," his memory was not poor.

Designs he had seen in school and the blueprints shared by a brother on the forum before the challenge had all left a deep impression on his mind.

If the content of the novels hadn't been so vast, and the text somewhat vague, he wouldn't have needed to ponder carefully to recall them.

After a moment of contemplation, he finally remembered that this salt-like mineral seemed to be natural potassium nitrate.

Potassium nitrate is potassium nitrate, often appearing in novels about traveling back to ancient times, sometimes used to make ice drinks in midsummer for cooling and relieving heat. More often, it is used to make gunpowder and glass or used as fertilizer, being an important raw material for industrial development and one regulated industrial material.

Verifying whether this mineral is indeed potassium nitrate is simple.

Just grind the potassium nitrate into powder, then pour it into a container filled with water and stir gently.

If this mineral is indeed potassium nitrate, it will absorb heat from the water during the dissolving process, causing the water temperature to drop.

When the water temperature drops below the freezing point, the water will begin to freeze.

Generally, the larger the amount of potassium nitrate, the faster the freezing speed.

While reading historical novels, Chen Zhou had indirectly learned the ancient method of using potassium nitrate to make relatively clean ice.

They usually used a large basin to hold a smaller basin, both filled with water.

On top of the nested basins, there was a lid to reduce the external environment's impact on the ice-making process.

Potassium nitrate dissolved in the large basin, affecting the water in the small basin through the basin wall, thus causing the water to freeze.

Due to the toxicity of potassium nitrate, which is a carcinogen, ice made in this manner is somewhat safer.

Moreover, after making ice, potassium nitrate can be extracted from the large basin again through recrystallization by cooling or evaporation crystallization, allowing for reuse and reducing damage.

In addition to ice making, potassium nitrate is also one of the raw materials for manufacturing black gunpowder and can be used as a material for ceramic and glass glazing.

"Making black gunpowder requires a higher purity of potassium nitrate.

Alas, unfortunately, I didn't pay much attention to chemistry after going to college, and I've completely forgotten the method of purifying potassium nitrate. Now I guess I can only use them to make ice or glaze pottery that hasn't even taken shape."

Flipping the hand axe, he used the hammer head to knock down the mineral attached to the cave wall; just as he was about to pack it in his climbing bag, Chen Zhou realized that he had left his climbing bag at the entrance of the passage earlier, and it was not with him now.

"I'll collect some first and leave them by the passage. I'll take them with me when I leave Pigeon Cave."

Thinking this way, Chen Zhou chipped away at the salt-like mineral bit by bit, gathered it together, and casually placed it in a deeper position of the cave.

After collecting about three kilograms of the mineral suspected to be natural potassium nitrate, he carried the oil lamp and continued moving forward.

The further he went, the wetter the ground became, and the sound of water grew louder.

Walking about a hundred meters, feeling that his altitude had decreased by at least 30 meters, Chen Zhou still hadn't seen the end of the cave.

Only the sound of water, a continuous and increasingly torrential sound of water.

"I can't go any deeper."

The sound of rushing water echoed against the cave walls, and something seemed to lurk in the darkness, giving Chen Zhou a foreboding sense of danger, prompting him to stop.

Lai Fu raised his head, his expression serious, the bird droppings on his paws partly washed off by the damp ground, revealing his light yellow fur.

Woof!

Barking softly once, Lai Fu turned his head, looking at Chen Zhou, then casting his gaze into the darkness ahead, toward the source of the water sound.

"Is there danger there?"

Chen Zhou petted Lai Fu's head, and unconsciously, his palm holding the axe handle was covered in a thin layer of sweat.

In Robinson Crusoe, the adventurous guy Robinson never delved deep into Pigeon Cave or reached such a place at night.

Since this wasn't a described location in the book, safety couldn't be guaranteed; any danger or accident was possible.

A wise man stays away from risky places, and with no powerful weapon for self-defense in hand, Chen Zhou dared not proceed further, deciding to retreat.

Moreover, it was already late at night; he had gotten up early, and logically he should have rested long ago.

Continuing to stay awake would lead to mental haze and increase the likelihood of accidents.

Besides, if this cave weren't so large and deep, and if he hadn't discovered the mineral suspected to be potassium nitrate along the way, he wouldn't have ventured this far.

...

With his mind made up, Chen Zhou retraced his steps along the cave wall.

Taking off his jacket to bundle up the chipped minerals, he squeezed through the narrow cave walls and exited Pigeon Cave.

That night, he slept near the woods at the foot of the mountain.

Exhausted after a night's exertion and traversing the dark and oppressive cave, Lai Fu was exceptionally tense, finally relaxing after leaving the cave.

Although Chen Zhou outwardly appeared unfazed, his subconscious was indeed affected.

Lying on the "bed" covered with fallen leaves and broken branches at the edge of the forest, that night, Chen Zhou "personally experienced" many classic scenarios from tomb raiding adventure novels.

He sometimes surfed and floated amid ancient coffins, sometimes scaled a solitary cliff straight upward, with boundless miasma below, and sometimes battled three to four-meter-long giant lizards...

Until the morning of July 1st, with the sun high in the sky, Chen Zhou was still engrossed in his dream.

As the story in his dream reached a climax, about to conclude, Lai Fu's wet, big tongue licked his face, disrupting the feng shui treasure land, reminding him it was time to wake up.

Scratching his head, lying with open eyes on the ground for a few minutes, Chen Zhou finally broke away from his roller-coaster-like dream.

He got up and felt hunger in his stomach, then directly started a fire on the spot, grilling a few pigeons for himself and Lai Fu.

The wild pigeons on the island were small, and Chen Zhou gobbled down five of them, still only being half-full.

Perhaps because they had been stuffed in the backpack overnight, the pigeons slaughtered the previous night didn't taste as fresh as he imagined.

Of course, it could also be due to the lack of seasoning.

There are few ingredients in the world that can turn into a delicacy with just a pinch of salt. Even if wild pigeons are excellent ingredients, they require other accompaniments; otherwise, there will always be a hint of gaminess.

Lai Fu, however, wasn't picky, easily gulping down the prepared pigeons, finishing half of those in the backpack.

Considering that some pigeons needed to be taken home to make soup, Chen Zhou forcibly ended the feast, organizing the dead pigeons and suspected potassium nitrate minerals in his backpack, and started to head home.

Passing by the river on the way back, he didn't forget to wash the bird droppings off Lai Fu's body and, incidentally, removed his own clothes for a cold shower.

Perhaps the cold water dispelled the heat, making his mind clear; he suddenly recalled that besides the wild pigeons and the suspected natural potassium nitrate minerals, there was another overlooked resource in the cave—bird droppings.

He had painstakingly composted but hadn't even dug a proper pit yet, with progress slow.

Little did he expect there to be such a resource-rich point of premium fertilizer not far from the riverbank.

With just a cart, wooden shovel, and pickaxe, he could scoop up those aged droppings, putting them to good use for his planting ambitions.