"Many spells that require elemental release, such as Aguamenti and Incendio, use the Element rune as their base. You combine other runes with these foundation characters to achieve the specific effect you desire," Professor Bones explained.
"So that's the logic. Does that mean spells that don't change an object's form generally use Control, those that do change form use Transformation, and the others use Element? Are there any other primary categories?" Alan asked, his interest fully piqued.
"Of course. Many memory-based spells use the Thought rune, while various Dark Arts spells, such as the Unforgivable Curses, are anchored by the Soul rune. Soul-related magic is extremely complex and profound, making it incredibly difficult to develop counter-curses or anti-curses. This is one of the main reasons why such magic is strictly forbidden," Professor Bones clarified in detail.
Having resolved the fundamental doubts in his mind, Alan continued to outline his project. "After using Control as the base—considering this spell needs to first emit sound waves and then receive them back—I'm trying to use the time interval and direction of the echoes to achieve a positioning effect. To do this, I've combined the Sound, Emanation, Sensing, and Presentation runes."
"Oh? Show me your proposed combination," Professor Bones said. Hearing that Alan already had a practical concept in mind, he wanted to observe the sequence to gauge the boy's progress.
"Alright, Professor." Alan skillfully summoned the necessary characters on the workbench. The Professor's table contained a vast collection of runes, so there was no issue of missing a character.
Bones studied the combined sequence and offered a small smile. "Have you attempted to cast this yet? Your magical control is quite high, so I imagine you've tried a field test. What was the result?"
Alan nodded. "I tried it, but after casting, the spell only produced a low buzzing sound. It was useless except for being noisy; I didn't receive any echo feedback at all."
"What do you believe is the cause?" Bones asked.
"This charm is meant to simulate ultrasonic waves, which require much higher frequencies. I believe the issue is that the current frequency of the sound wave is insufficient," Alan stated.
"I think I understand your logic, but there is one place where your sequence has gone wrong," Professor Bones noted, leaning closer to the display.
"Where?" Alan's heart stirred. A professional's eye was clearly different.
"Here," Bones said, pointing to a specific junction.
"Is there a problem with the Presentation rune?" Alan asked, puzzled.
Professor Bones nodded. "Precisely. Your idea is to emit high-frequency waves, receive them, and use the data to detect your surroundings. How far do you envision the range to be?"
Alan thought for a moment. "Ultrasonic waves are very fast and stable. At the very least, it should detect a radius of a hundred meters. With rune optimization and the right casting techniques, reaching a thousand meters should be no problem."
*Such a wide range?* Bones was secretly surprised. Although he didn't fully grasp what Alan meant by "ultrasonic," if such a wide-ranging detection spell could truly be developed, its applications would be massive. The Super-Sensing Charm, a standard perception magic, only reached a few dozen meters at a master's level.
Bones nodded slowly. "Alright. Then have you considered how you will process that information once you receive it from such a vast area? Will you hear it, or see it? If the data is attached to your eyes, the overlay might interfere with your actual vision."
Alan was stunned. He had thought through the physics of the sound, but he hadn't considered the user interface. His ears certainly couldn't process a thousand meters of 360-degree echoes. If his vision was suddenly filled with sound-wave patterns, it might blind him to his actual surroundings. Furthermore, Alan envisioned this as a total, no-blind-spot detection mode; eyes only look in one direction.
Professor Bones watched the boy fall into a deep reverie and explained, "The idea is excellent. This kind of spell would be perfect for detecting things behind cover, or in environments with poor visibility like dense forests."
"Exactly," Alan said. "And I also envision it being able to pick up people using the Disillusionment Charm or even wearing an invisibility cloak."
"Oh?" Bones hadn't considered that, but it significantly increased the value of the charm. "I'll offer you two approaches. The first is to transmit the feedback directly to your mind, allowing you to visualize the environment. The Legilimency rune has a similar application, but the development difficulty is immense and the risk of mental injury is high. I don't recommend it. The second approach is to dismantle your charm. Try using an alchemical tool to receive and present the information—a mirror or a pair of enchanted glasses. The spell would emit the waves, and the tool would process the return. This would be far safer and much easier to develop."
"Understood. I'll go with the second method," Alan replied after a moment's thought.
*As expected, an experienced scholar has a much clearer perspective,* Alan mused.
"Alright, let's stop here for today. To achieve what I've described, you still need to learn quite a bit about material science and enchanting. I will begin explaining those topics next time."
When Alan finally left the office, it was well past curfew. He decided it was more sensible to return to the Slytherin dormitory rather than trekking back to the hut in the dark.
As he walked toward the dungeons, Alan replayed the lesson in his mind. Professor Bones was a true master; the amount of information he had gained in one evening was richer than months of self-study.
He reached the third floor when he heard a faint rustling behind him. He spun around just as two shadowy figures lunged from the darkness.
Instinctively, he threw up a barrier that sent the shadows bouncing back. Upon hitting the wall, the objects burst open, and a foul, overpowering stench filled the corridor.
"Dungbombs?" Alan manipulated the air around him, a gust of wind blowing away the filth and the smell as he ducked behind a stone pillar to scan for the attackers. But the ambushers had already vanished into the shadows.
*Attacking me at the very start of the term? Who else but Travers and his gang,* Alan thought, his brow furrowing deeply. *How childish.*