Chapter 147: The Prism Principle

Professor Babbling's question sent Edward to the alchemy shelves with a narrower purpose. He needed a material that could hold a small magical charge, release it through a fixed ward, and fail without exploding.

Silver conducted magic well but did not retain much. Clear crystal retained a charge but fractured when magic entered unevenly. Combining them carelessly produced exactly the sort of sharp, enchanted debris Madam Pomfrey had forbidden him to create near students.

Professor Snape agreed to discuss the problem after Edward submitted the design and safety notes in writing.

"You have finally discovered paperwork," Snape said. "A rare branch of magic that prevents other people from cleaning up your mistakes."

On his desk lay three sealed samples: a silver ring, a clear crystal bead, and a sliver of moonstone. Snape did not allow Edward to touch any of them until he had identified the likely hazards.

"The crystal may split along an invisible fault," Edward said. "Silver could carry the charge into the hand. Moonstone might alter the timing because it responds to cycles rather than direct intent."

"And the fourth hazard?"

Edward studied the arrangement. "The person performing the test."

"At last."

They began with magic no stronger than Lumos. Edward placed the crystal bead inside the silver ring and sent a thread of light through it. The crystal brightened, then released the light all at once. The silver became hot enough to scorch the protective mat.

The second attempt added moonstone between crystal and silver. The light entered more slowly, but the bead retained a ghostly glow after Edward ended the spell.

"Residual charge," Snape said. "Unacceptable for something carried in a pocket."

Edward recorded the failure. The third arrangement used a thin silver cage around a larger piece of clear crystal, leaving space for heat to escape. The charge moved evenly and faded when he lifted his wand. No afterglow remained.

It still did not hold the ward.

For that, Professor Babbling joined the next session. She carved the termination sequence onto a separate clay tile while Edward traced the directional and recognition marks on paper. Snape inspected the sequence for places where trapped magic might build pressure.

The professors disagreed over one stroke for twenty minutes.

Edward watched instead of interrupting. Their disagreement revealed more than instant approval would have. Babbling read the stroke as a boundary. Snape argued that, in an alchemical setting, the same shape might behave as a closed channel. They solved it by opening the line and adding a distinct ending mark.

The revised silver cage accepted the sequence. When Edward charged it, pale light traveled around the crystal and stopped at the termination mark. He lifted his wand. The light vanished.

"Again," Snape said.

They repeated the test with half the charge, then with Edward's hand shaking from a simple balance exercise. The prism released a crooked shield and went dark. It did not crack.

That failure pleased Edward more than the earlier success. The device had produced a poor barrier when the bearer supplied poor control, but it had not multiplied the mistake.

Professor Babbling turned the small object beneath a magnifying lens. "This is a setting, not yet a talisman. What will you call it?"

Edward had crossed out grander names in his notebook. "The Heart Prism."

Snape made a faint sound of disapproval.

"It identifies the project," Edward said. "It does not claim the object contains a heart, soul, memory, or emotion."

"Put that disclaimer on the first page."

Edward did.

The Heart Prism held only a limited charge and the shape of a reviewed ward. Its clear center let the bearer see discoloration or cracks before use. The silver cage remained open enough to vent heat. A removable clay seal carried the recognition mark, which meant the bearer could break that seal to erase the attunement without destroying the rest of the setting.

They tested that feature next. Edward charged the prism, then snapped the clay seal. The light died. When he tried the release phrase, nothing happened.

"Good," Professor Babbling said. "Consent that cannot be withdrawn is merely ownership with better manners."

The project still had serious weaknesses. The prism was too large for a bracelet, and striking it directly might drive crystal fragments into the hand. Recharging required a professor-level inspection of the rune sequence. It could not distinguish a training jinx from a lethal curse; the bearer still had to choose when to use it.

Edward listed each weakness on the cover rather than hiding it in later notes.

He also abandoned the plan to connect the prism directly to a wand. The early sketch would have allowed the device to alter a spell as it left the wood. Neither Snape nor Babbling could predict how that interaction might affect allegiance, aim, or the magical substance inside the wand.

"A wand is not a handle for your invention," Snape said.

The sentence ended that branch of research.

Flitwick supervised the first attempt to place a Shield Charm shape into the setting. Edward cast Protego through a frame beside the prism rather than through the object itself. The silver sequence caught a faint copy of the arc, while the spell continued normally from his wand.

When the prism released that stored shape, a translucent barrier appeared for two heartbeats. Flitwick tossed a padded ball against it. The ball slowed, touched the barrier, and dropped.

"No reflected force," Edward observed.

"Which is safer in a crowded corridor," Flitwick replied. "A shield that throws an attacker backward may throw a frightened first-year down a staircase."

They increased neither strength nor duration. Instead, they tested direction. Held correctly, the arc opened away from Edward's palm. Held backward, the termination mark ended the working before a barrier formed. Dropped on the floor, it remained inert.

The prism failed six times that afternoon. Once the recognition seal did not answer. Twice the barrier leaned. Once the silver cage grew warm. On the final two attempts, nothing happened and no one could determine why.

Edward wrote all six failures beside the single success.

At dinner, Draco asked whether the new talisman would be ready by summer. Edward answered that it was not a talisman yet and might never become one. Draco looked disappointed.

"Then why spend so much time on it?"

"Because learning that an idea is unsafe before giving it to someone is also a result."

Theodore, seated across from them, nodded. "Put that on the alliance copy."

Edward did that too.

By the end of term, the Heart Prism could produce a brief forward barrier under classroom conditions. It could not be trusted in combat. The next stage required controlled breakage tests, a safer casing, and adult supervision at 12 Grimmauld Place.

Dumbledore approved the summer work on three conditions: Sirius would act as guardian, a qualified adult would review each new material, and no alliance member would wear a prototype until the professors received a written report.

Edward accepted all three. The prism went into a padded wooden box with the broken prototypes beside it. A dated seal would reveal any unsupervised opening. Success and failure traveled together.

The box seal bore the date, supervisor names, and an inventory. Any missing fragment would halt the summer project before another test began.