After returning home, Chiba finally asked Gray Yuan Wai his puzzled question.

"Were you scared? What's going on? ”

“。。。” Gray Plains pursed his lips and did not answer.

“。。。” A wave of uneasiness welled up in Qian Yu's heart. Gray Yuan Wai has no intention of saying anything at all, but Qian Yu is now ruthless to drive Gray Yuan Wai out. So...

So Qianyu decided to give her house a high-intensity armament.

"You don't want to say ... Needless to say... Qianyu sighed. I will arm the house as soon as possible and prepare it for defense. ”

Gray Yuan lowered her head and didn't say a word—if there was stubbornness in her expression before, now her expression was more guilty, guilt for not being able to explain the truth to Qianyu. (Of course, Chiba can't see it)

Just then, the phone rang - it was Dr. Asasa calling.

As Fujiwara had said, Dr. Asa invited all the members of the Junior Detective Corps to join him the next day at a hot spring hotel in the suburbs.

"When we get there, are we going to help the guy named Fujiwara spy on that girl?" Gray Yuan Ai watched Qian Yu hang up the phone and asked.

"It's not a good habit to take on a task and not do it," Qian Yu shrugged. "But if the mandate is too much, we can reject it on judicial grounds."

"That's right." Gray Plains nodded.

"Then I'm going to make you dinner first?" Chiba stood up and walked to the kitchen. "What are you going to eat?"

"Let's freeze dumplings... After hesitating for a moment, Gray Yuan said softly. "It's easier to do...

"Okay." Qian Yu walked to the refrigerator and took out the quick-frozen dumplings.

"I'm sorry... Ash Hara's wailing turned around and muttered in a voice that only she could hear. "I'm really sorry...

。。。

The next morning, a Beetle was driving down the road.

"Hakone Onsen?" Ayumi said curiously. "Where is that?"

A hint of discoloration flashed in the eyes of Thousand Feathers and Conan.

"Ayumi you don't know about Hakone Onsen?" Mitsuhiko was surprised. "That's the hot spring town!"

"Can you elaborate on that?" Gray Yuan tilted his head and looked at Chiba. "I don't understand this."

"Hmm... Qianyu pondered for a moment. "Hakone is part of the Mt. Fuji Scenic Area, located in the southwest of Kanagawa Prefecture. The main attractions include Hakone Nanayu, the seven most famous hot springs in the Hakone area during the Meiji Emperor's reign, and Hakone Hachiri, among others. ”

"There's a delicious food over there!" Dr. Asasa said with a smile.

"Food?" At this time, even Qian Yu looked at him in surprise.

"Black jade who has extended his life for seven years! Legend has it that eating a black egg can extend your life for seven years! Conan reminded. This is a specialty of Owakudani! ”

"I knew about black jade before, but I didn't know that black jade was something here... Thousand Feathers shrugged. "By the way, I remember that because black jade seeds are steamed in hot springs, the egg yolk is more delicious than ordinary eggs?"

"Yes," Dr. Asasa nodded. "The lake inn we went to is near Yonggu, and if I remember correctly, there should also be a small hot spring that can steam black jade seeds, and we might be able to buy some directly there and taste it... I suddenly remembered a riddle, how about you guess? ”

“？” Everyone looked at Dr. Asasa.

"There's a flood above, there's a fire below, what's the mystery?" Dr. Asasa gave the question.

"Uhhh Both Chiba and Conan reacted immediately. "Doctor, isn't this going to be too easy?"

"It's a hot spring!" Motota, Ayumi and Mitsuhiko all gave answers in the first place.

"That's not a good fire, is it?" Gray Plains tilted his head. "Most of the hot springs are produced by underground magma heating flowing water, but what does underground magma have to do with fire?"

"But it looks similar." Qian Yu pursed his lips. "Although it really doesn't matter at all...

"Doesn't magma have anything to do with fire?" Motota, who was in the co-pilot's seat, turned around and asked curiously.

"Magma is mainly composed of molten silicates and metal oxides, and is solid in itself, completely independent of flames." Gray Yuan said lightly.

"But the lava is fiery red!" Ayumi asked. "Isn't that a flame? If there were no flames, how could there be that color? ”

"The color of the magma itself is different at different temperatures... Thousand feathers spread their hands. "Above 475 degrees, red will appear; Above 550 degrees, there is a dark red; Bright red above 700 degrees; Orange above 900 degrees; Golden yellow above 1090 degrees; Above 1150 degrees, magma will appear white. Theoretically, blue or even purple magma would have appeared if the temperature had been higher – but the magma that could reach temperatures of 1,875 degrees Celsius at atmospheric pressure has long since disappeared, leaving only relics like komatiite to prove its existence. ”

"Why is it long gone?" Ayumi asked.

"Over time, the mantle cools, and only billions of years ago magma can reach that temperature at atmospheric pressure and form komatiite. Now in the same process, only much colder magnesia can be formed. (Translated as peridot in China, but the word itself comes from the Japanese "magnesium", that is, kaodao, so this story in Japan chooses to respect the original meaning of the Japanese)" (wiki data shows that the temperature of the Komati magma is 1600 degrees Celsius, but the 1989 Campbell I·H paper indicates that the temperature of the Komati magma at 0.99 times the atmospheric pressure is 1875 degrees, and the most cutting-edge information that Chiba could access at that time was campbell I·H, So that's what it takes. Also, according to the same paper by Campbell, the temperature of peridotite is 1425 degrees Celsius. ）

"Then why does the mantle cool?" Ayumi asked again.

"Heat dissipation to the surface..." Chiba replied. "It's a very slow process, but the heat from the mantle and core is constantly being transferred to the surface – but it's too slow, so the temperature of the mantle and core doesn't drop much until the sun turns into a red giant and swallows the Earth."

"Qianyu is so erudite... Mitsuhiko sighed.

"Don't make fun of me!" Qian Yu smiled bitterly and waved his hand. "I just happened to see that paper, and how could I have known these things if I hadn't read that Campbell paper!"

"Well, that's it!" Dr. Asasa suddenly said happily. "Lake View Hotel!"

Ahead, the six- or seven-story main inn building occupies the end of the view.

"Claiming to be a hotel... The corners of Chiha's mouth twitched. "This scale can be regarded as a hotel in a grand manner. . . ."

"This hotel has just been expanded for a few years, and before that Huwang Hotel was very small!" Dr. Asasa explained with a smile.

"Doctor, are you familiar with this shopkeeper?" Conan wondered.

"We were classmates in college, but he inherited the hostel after graduation and I went on to pursue a degree, so we parted ways. However, I was invited by him many times during my college years to soak in the hot springs! ”

Amid the conversation, the Beetle drove into the parking lot.