After speaking, Chu Chen had someone search for the white crystalline substance in the corner.
This was the famous niter!
Niter found in nature is often formed when nitrogenous organic matter in the soil decomposes and oxidizes into nitric acid under bacterial action, and then combines with potassium in the soil.
As the summer weather gradually cools, or during the crisp autumn season, it precipitates in the form of crusts or salt flowers, covering the ground and the base of walls.
This is what is known as ground frost.
Speaking of niter, its uses are vast.
One niter, two sulfur, three charcoal, add some white sugar, and it's a great concoction.
Using niter, sulfur, and charcoal, the most primitive black powder can be manufactured. Adding white sugar can further enhance the explosive power of the gunpowder.
Another use of niter is in the production of ice.
Niter dissolves very easily in water, and it also lowers the temperature of the liquid when it dissolves.
Simply fill a water vat with water, then add a large amount of niter. Place a jar filled with water inside the vat. It won't take long for the water in the jar to freeze.
This is the method of making ice with niter.
With niter, even in the scorching summer, ice can be obtained!
Most importantly, niter can be reused.
Simply boil the water containing niter until it evaporates, and the dissolved niter will precipitate out, allowing for repeated use.
Of course, the amount of niter Chu Chen currently had was definitely not enough. Let alone making ice, it could probably only lower the water temperature slightly.
Therefore, he immediately dispatched people to search for similar substances throughout the entire city.
He didn't neglect the villages in the countryside either.
Relatively speaking, these substances were more likely to be found in the corners of old houses or animal enclosures in villages.
This action, however, greatly puzzled Princess Xin Yue.
"What are you looking for these things everywhere for? Can these things really make ice?"
Meeting Princess Xin Yue's confused gaze, Chu Chen nodded firmly, "Yes, these things alone can make ice!"
Princess Xin Yue found it absurd.
If ice could be made with these things, why would the imperial palace dig such large cellars and expend so much effort every year?
Princess Xin Yue watched Chu Chen busy himself with a cold gaze. If Chu Chen couldn't produce what she wanted, she would punish him severely!
Chu Chen busied himself for a long time, and finally, a bucket of white crystalline niter mixed with black mud was presented.
Chu Chen had people pour these things into a large vat and filter out the impurities.
Next, he had a large pot set up, water poured in, and heated over a high flame until white crystals began to precipitate in the pot.
After repeating this process several times, what was finally presented was large handfuls of snow-white crystals.
Seeing this, Princess Xin Yue, who had been very skeptical before, couldn't help but feel a flicker of interest.
"To be able to produce something so white as snow is quite interesting."
Looking at these niter crystals, Princess Xin Yue was tempted, but thinking that they were extracted from such foul substances, her face showed disgust.
"Is this your so-called ice?" Princess Xin Yue's gaze towards Chu Chen now held a hint of anger. "Are you trying to fool this princess with these things? Do you think this princess is a fool?"
"This subject dares not, but this is not the finished product," Chu Chen explained, then smiled slightly, "The next part is the moment to witness a miracle!"
Saying this, Chu Chen had another large pot set up. This time, however, he did not heat it. Instead, he placed a jar inside the large pot and then continuously added white crystals to the large pot.
In just a moment, a fine layer of small water droplets formed on the outside of the large pot.
This was water vapor from the air condensing on the surface of the pot due to the cold.
"Princess, please reach out and touch it," Chu Chen said with a smile.
Princess Xin Yue, with a look of curiosity, tentatively reached out and touched the large pot. She then let out a startled cry.
"It's actually cold!"
"How can it be cold?"
Princess Xin Yue's eyes were filled with curiosity. As if she didn't quite believe it, she tentatively put her hand into the water and found that the water in the large pot was even colder.
"How did you do this!" Princess Xin Yue exclaimed.
"These white things are called niter. Niter dissolves in water and causes the water to cool down, and then it becomes what you see now."
Princess Xin Yue nodded, seemingly understanding but not entirely. Although she didn't understand what Chu Chen was saying, this incident showed her that Chu Chen had some skills.
"Mm-hmm, so that's how it is. This princess completely understands." Princess Xin Yue said with a determined expression, though in reality, she hadn't understood a single word.
Anyway, it was just a matter of putting this stuff in, and then it would cool down and freeze.
"But how did you know that this kind of thing could produce ice?" Princess Xin Yue asked with great confusion.
Chu Chen was momentarily speechless. He couldn't possibly say that he learned this from his teacher in his previous life.
"To answer the Princess, this is a medical method I saw in an ancient book before entering the palace," Chu Chen fumbled for an explanation.
"So that's how it is!" Princess Xin Yue said thoughtfully, "What is the name of that ancient book? I'll send someone to look for it later. If I give it to the Empress, she will be very happy!"
Even though she wasn't interested in reading, she was intrigued by this clever trick of making ice with all sorts of miscellaneous items.
Chu Chen put on a thoughtful expression. "This subject remembers, that book was called... Chemistry!"
Chu Chen knew that if he didn't provide an answer, Princess Xin Yue would pester him relentlessly.
"It's just a pity that I was young at the time, and after reading it, I lost the ancient book somewhere," Chu Chen feigned regret. "If Your Highness can find it, please allow this subject to see it."
Princess Xin Yue nodded repeatedly. "Don't worry, once this princess finds it, I will inform you immediately!"
Chu Chen breathed a sigh of relief. He had finally managed to fool the Princess.
After thanking the Princess, Chu Chen demonstrated the process to his subordinates and then had them move the ice-making operation outdoors.
It was too hot to burn such a large fire in this sweltering weather.
As for the ice that had already been made, Chu Chen had it taken to the kitchen, broken into pieces, ground into powder, and then drizzled with milk and honey.
Before long, two bowls of shaved ice emitting cold mist were served to Chu Chen and the Princess.
Princess Xin Yue scooped a small spoonful with her spoon. The sweet aroma of the ice mixed with honey and milk made her eyes squint with happiness.
Eating too eagerly, Princess Xin Yue got a little honey on her nose and lips, which made Chu Chen quickly avert his gaze.
A feast for the eyes, indeed.