Jin and his companions had arrived at a section dedicated to Material Science.
"Heh, they’re doing quite a lot here."
"Interesting, isn't it?" Saki asked.
"Intriguing," Elsa added.
A few dozen alchemists had set up booths, each displaying various wares or performing demonstrations for the passing crowds.
"Hmm? This smell..."
Saki’s nose twitched, her face suddenly went pale, and she yanked on Jin’s sleeve.
"J-Jin! It’s dangerous here!"
She had once nearly lost consciousness after inhaling sulfur dioxide during an experiment involving burning sulfur. The scent alone was enough to bring those memories rushing back.
"Eh?"
Looking ahead, Jin saw an alchemist at the nearest booth heating sulfur in a pan-like container. It was beginning to melt, and the sharp odor Saki feared was indeed rising from it.
"Ah, you’re worried about the sulfur dioxide."
Jin pulled a handkerchief from his pocket and used 'Condense' to gather moisture from the air, dampening the fabric. He held it over his nose to demonstrate.
"See? If you do this, a small amount is perfectly safe."
Sulfur dioxide—or sulfur dioxide gas—dissolves easily in water. When someone encounters it, such as near a volcano, a wet towel can provide temporary protection. Of course, it isn't a perfect shield, so one should still evacuate the area as quickly as possible.
Jin dampened Saki’s handkerchief as well. Elsa used 'Condense' herself and pressed her own wet cloth to her face.
"...Hmm, I see."
With the wet handkerchief in place, the smell of sulfur dioxide vanished. In truth, very little was being produced to begin with. The alchemist wasn't burning the substance; he was merely heating it.
The man ignored them and calmly continued his work until the sulfur in the container had completely melted into an amber-colored liquid.
"Now then, if I pour this into water..."
The alchemist gripped the handle and poured the molten sulfur into a bucket of water. The viscous liquid flowed out like trailing threads, cooling and solidifying instantly. He fished the result out and held it up.
"Behold! Brittle sulfur has become as flexible as this!"
He pulled at it as he gave his pitch. It possessed a rubber-like elasticity, expanding and contracting with ease.
"...Heh, Jin, that’s fascinating! I once tried to use the smoke from burning sulfur to bleach flower petals, but I ended up inhaling it and passing out. This looks much safer."
"Saki-nee, sulfur dioxide is very dangerous..." Elsa said, her voice tinged with exasperation. It seemed she was also well aware of the risks.
"But if you can make rubber out of sulfur, think of the applications!" Saki exclaimed.
Jin, however, was quick to temper her excitement.
"I’m sorry, Saki, but that’s called plastic sulfur. It happens when you flash-cool molten sulfur, but it's temporary. It’ll return to its original brittle state after a while."
"...Is that so? That’s a shame..."
They had been whispering, but the alchemist apparently had keen ears. He shot a terrifying glare at Jin and the others. It was clearly a nuisance to have someone spoil the secret behind his demonstration right in front of his booth.
The group beat a hasty retreat.
Next, they stopped at a booth displaying a wide array of minerals. It felt quite similar to Saki’s own collection.
"Jin-nii, they’re pretty."
"Yeah, they really are."
Red, yellow, green, blue, purple—minerals of every conceivable color were on display.
"Now then, young lady, witness this golden stone," the alchemist said.
He held up a gold-colored stone about the size of a fingertip. He then took out a flat, white stone and rubbed the golden one against it. One might have expected it to leave a golden streak, but instead, it left a dark, blackish line.
"Heh, so it’s not gold?" Saki said, sounding impressed.
"Exactly. This is how one distinguishes true gold from the many stones that mimic its appearance," the alchemist boasted proudly.
This time, Jin and Elsa whispered to each other so softly they were certain not to be overheard.
"(...The streak test, right?)"
"(Yeah. That’s probably just pyrite.)"
It was an experiment commonly taught in basic science. Jin and Elsa recognized it immediately, but Saki was genuinely intrigued and spent a long time chatting with the alchemist.
"...If you knew what it was, you could have just told me."
"Sorry. You looked like you were having so much fun that I didn't want to interrupt."
When Saki finally returned to them, Elsa had accidentally let the term "streak color" slip.
"Saki-nee, I’m... sorry."
After being scolded, Elsa looked quite dejected.
"B-But looking at it like this, alchemy truly seems like a field with a lot of potential!" Jin said, desperate to change the subject. "Researching things that can be applied to daily life without relying on magic—it's impressive."
"...Do you really think so?" Saki asked. She still had a bit of a pout, but her mood seemed to be lifting.
"I do. It’s just a shame it hasn't been properly systematized yet."
Jin’s observation seemed to resonate with Saki.
"Systematized, huh... You’re right. Within alchemy, Magic Theory and Magicology are well-established, but Material Science is still in its infancy."
Material Science aimed to investigate the properties of various substances without using magic, then apply those findings to everyday life. The field—essentially the equivalent of chemistry—had only just begun its journey. It was no surprise that a cohesive system had yet to emerge.
"I’ll want you and the others to teach me about it from now on," Saki said.
"Of course."
"Hehe, I’m looking forward to it."
As the three of them completed their circuit, they saw a young male alchemist on a central stage holding up a flask of purple liquid. The container appeared to be made of clear crystal.
"This is juice extracted from Purple Ganran," he announced.
Purple Ganran was a vegetable very similar to a cabbage, distinguished by its deep purple hue. Essentially, it was a red cabbage equivalent.
"If I add a few drops of vinegar to this juice..."
A cheer erupted from the crowd as the purple liquid turned a vibrant red.
"Next, I will add the clear runoff from lye..."
The red liquid shifted back toward purple, then blue, then green, and finally settled on a bright yellow.
"No magic was used whatsoever. While this is still in the testing phase, I believe these properties could be utilized for advanced dyes. That is all."
The audience gave him a generous round of applause. That appeared to be the end of the scheduled events.
"With that, today's live demonstrations have concluded," an official announced over the speakers. The spectators gathered around the stage began to disperse.
"Ah, that was fun."
"Jin, I’m going to head back to my booth now."
"Yeah, I’ll do the same."
Parting ways with Saki, Jin returned to his own booth, only to find it surrounded by an enormous crowd.
"Ah! Jin-dono!"
"Wait, is that Jin-dono?"
"Jin-dono! Please, tell us more about these Mini-Smiths!"
Now that the formal demonstrations were over, the engineers and craftsmen who had been impressed by Jin’s work earlier had descended upon him in droves. Dealing with the inquisitive mob turned out to be the most exhausting part of Jin's entire day.
And so, the first day of the Technology Expo drew to a close.
"Whew, I’m beat."
Back in his hotel room, Jin slumped into a sofa. Acting as a public figure was far more draining than he had anticipated.
"Father, please have some Persica juice."
Reiko offered him a glass of Hourai Island’s special blend. A single sip was enough to provide a burst of energy and wash away his fatigue.
"...Oh, that smells wonderful."
Just then, Elsa emerged from the shower, catching the sweet scent of the fruit.
"Do you want some too, Elsa?"
"Mhm."
A chilled juice was the perfect follow-up to a hot shower. Eschewing any unladylike gestures, Elsa finished the drink with quiet grace.
"...Thank you. That was delicious."
"I think I’ll go jump in the shower myself," Jin said, standing up.
Mine stepped forward and handed him a fresh towel. "Jin-sama, here you go."
"Ah, thanks."
While Jin showered, Reiko laid out a change of clothes for him. When he finally returned to the living room, feeling much more refreshed, he found that Saki had dropped by. Ar was standing by her side.
"Evening, Jin."
"Hey, Saki. What brings you here?"
"Well, I have a room to myself and I was getting bored. I didn't want to go and disturb Reinhard and Bell, so I figured I’d come hang out here."
"Haha, makes sense."
Jin gave Reiko a nod, and she served Saki a glass of Persica juice as well.
"Oh, thank you, Reiko-chan."
Saki thanked her and downed the juice in a manner that was significantly less refined than Elsa's.
"Saki-sama, please try to be a bit more ladylike," Mine chided. Saki, however, conveniently developed a sudden case of deafness.
"I heard a bit from Reinhard. It sounds like Elsa and Mine’s return to the empire is going to happen?"
"Yeah. We received Her Majesty’s official recognition today. Now we just have to persuade Elsa’s father and... the marchioness."
"True. Those two are going to be a handful, for sure..." Saki laughed, then turned to Elsa and Mine with a sincere expression. "Elsa, Mine, I’m happy for you."
"Saki-nee, thank you."
"Thank you very much, Saki-sama."
Saki immediately bounced back to her usual energetic tone.
"Oh, that reminds me! Jin, I was so busy submitting and explaining my papers to the Alchemists' Association today that I missed your demonstration. I’ll definitely be there tomorrow!"
Jin gave her a confident smirk.
"Yeah. Make sure you don't miss it."