In the end, using a Mana insulation plate solved the problem of interference with the cooling spell.
It costs a bit more, but this is one part that's hard to swap out for another material.
What's left is the Mana instructions from the Control Panel to the main unit. The Mana Communication spell that links the Control Panel and the main unit is already done.
What I need this time is the control part that uses that link to start and stop the Magic circle when the time comes. If I just wanted to stop it, I could add dark attribute magic and cut it off easy, but that would only cut the flow of Mana. What I need is control that switches things at the exact time I set.
So then... I need to base it on the Magic clock's time control spell and adjust how it connects to the Mana Communication spell. If I add the dark attribute spell into the part I redrew... no, that's not right either. Maybe I should step away from dark attribute for now-
"You can do it with dark attribute, you know," Philip said out of nowhere.
I snapped my head up at Big Brother Philip's voice.
"But dark attribute only blocks Mana, right?" I asked, turning to face him.
"That's one way to use it, isn't it?"
I blinked in confusion. "Huh?"
"Dark attribute doesn't just block Mana. It can also suppress the flow."
I tilted my head. "...Suppress?"
"Instead of letting Mana flow all the time, you control it so it only passes through when you need it. It's a basic idea in the Magician Corps, but... maybe it's not used much in the Magic Tool field?"
"Yeah, this is the first I've heard of it. Grandpa might know, though."
...I see. So you use dark attribute not to stop Mana, but to control it. So then, if I add the Mana Control spell into the part I just redrew-
"...What. That's easy," I muttered under my breath, feeling like the wind got taken out of my sails.
"Getting to that point is the hard part," He laughed at me again, giggling.
Whatever. Anyway, the problem's solved, so-"I'll have some tea too."
The tea had gone completely cold, but it was just right for my dry throat. After one sip, I finally felt some of the tension leave my shoulders.
"I think I'll get back to work now," With that, Big Brother Philip headed back to the workbench.
...Big Brother Philip, you left only one of the baked sweets I was planning to eat. Well, I guess I should be glad you left even one. I must've been using my head more than I thought.
The sweetness of the baked sweet spreads through me... I grab a sandwich too and eat it.
Come to think of it, I've never had a katsu sandwich1 in this world. I think I could get the ingredients together, but... cooking it is a different story. Man, I'm craving a katsu sandwich now. I kinda know how to make one, so maybe I'll ask the Head Chef next time. If it's the Head Chef, he'll probably recreate it perfectly.
After one more cup of tea, I guess I'll get back to work too. Break time's over, and I headed back to the workbench.
First, I need to adjust the control spell with the dark attribute built in.
I let a tiny bit of Mana flow and check the spell's reaction. If it's too strong, the Mana gets blocked. If it's too weak, the control gets sloppy. I fine-tune the spell one spot at a time, searching for the middle ground.
-The spells are a little too close together. But if I move them apart, the Mana flow changes...
...No. If I switch the spell-drawing pen's tip to a thinner one, I can keep a bit more space between the spells. It's cutting it close, as the pen tip is about to get crushed. I need to go to Lilien Trading Company again soon.
"Alright, done!"
I looked over at Big Brother Philip, and the cooling Magic Tool was finished. I tried running it, and-
I shivered, blasting out a sudden yell. "Cold!!"
"Big Brother Philip! You didn't adjust the Mana amount, did you?!"
"No, I did adjust it?"
"And this is the result?"
"...It just got a little stronger."
...Having a lot of Mana sure is rough.
"Anyway, turn that off! It's freezing!"
"Ah, I know," With that, Big Brother Philip stopped the Magic Tool right away.
"Man, I'm no good at fine-tuning Mana amounts. Finn, can you do it for me?" Philip sighed, running a hand through his hair.
"Got it," Checking the Magic Tool, I follow the Mana flow to find just two spots that need adjusting. This much won't take long.
I erase the unnecessary parts with the spell-fixing pen, then redraw a stroke with the spell-drawing pen. Then I run Mana through it and check the reaction.
After fixing the last spot the same way, the Mana flow stabilized.
"Okay, done."
"Thanks. Let's try it again."
This time, a comfortable coolness slowly filled the room. This should be fine.
"Now we can live without ever worrying about the heat."
"No, that's not happening. You're gonna carry this around everywhere? Then you'd be better off with a Folding-Fan Magic Tool-"
"Folding-Fan Magic Tool?" Philip asked.
"This thing," I handed the Folding-Fan Magic Tool and its specs to Big Brother Philip.
"...I see. This Folding-Fan Magic Tool is an application of the Cooling Magic Tool, huh?"
"Yep. Carrying around a Cooling Magic Tool isn't realistic. With this, you can stay cool even while moving, right?"
"It's definitely handy. I don't think Father or Big Brother had one-is it new?"
"Yeah. Just for Mom, Tiana, and Uncle Alex."
"I see. Mom and Tiana would love that," Big Brother Philip stared at the Folding-Fan Magic Tool.
...Yep, I knew he'd say he wants to make one too.
"Alright, let's make one right now!"
Trivia:
- Big Brother Philip knows dark attribute can suppress Mana flow, a concept standard in the Magician Corps but rare in the Magic Tool field, hinting at a gap between military and civilian magical knowledge in this world.
- Finn's craving for a katsu sandwich, a dish that does not exist in this world, quietly reinforces that he is a reincarnated or transported person carrying memories of Earth food.
- Philip leaving only one baked sweet behind shows a teasing but affectionate dynamic, and Finn's mild reaction suggests he is used to his brother's snack-stealing habits.
Translation Notes:
1 ↩ A Japanese sandwich made with a breaded, deep-fried pork cutlet. The dish does not exist in this fantasy world, so Finn's craving hints at his otherworldly origins and Earth memories.
Notes:
• Philip - Big Brother to Finn and knight. Loves magic and learned Magic Tool crafting from Grandpa. Serves in the Knight Order and often moves between his room and the Captain's office.
• Finn - Third son of a marquis family and a magical tool maker. Graduated from an academy and became a full magical tool maker after apprenticing. Currently staying at the family estate during summer. Working on a prototype magical tool that can cool the air, using a fan blower's magical circuit as a base. Has a tendency to forget meals when absorbed in work, though this has improved. Finds the dining room and hallways uncomfortably hot. Wears his shirt with two buttons undone at home. Knows Noah well since childhood. Third son of a marquis family living in the royal capital. Aspiring magical tool maker who retains memories of a past life. Currently working on creating a cooling magical device to deal with an unusually hot summer. Gets absorbed in work and loses track of time.
• Tiana - Younger sister who returns from the academy. Complains about the cold Workshop and worries about their mother. Curious about her brother's inventions.
• Alex - Owner of Lilien Trading Company. Called Uncle Alex by Finn. Experienced merchant with an eye for sellable goods and a close, familiar relationship with Finn's family. Practical about product development and eager to commercialize new magical tools.