Chapter 153: Much Ado About Light

William Oh stared directly at the sun and the sun blinked first.

• Jason Salazar

Will reflexively unloaded every remaining weapon in his Phantom Hand. He didn’t have any weapons, but healing potion bottles were made of glass and when hardened by the manifestation ability, they were stronger than steel. Despite being blunt they could do a respectable amount of damage.

Will copied the glass vials and sent them cutting through the air at several hundred miles an hour, creating sharp cracking noises as he released them.

While he did, that he dodged to the side and scampered up the wall like a spider. No sense standing still and letting Ghoul hit him.

After a few seconds of Will systematically pummeling Ghoul’s last known location, Charnesa’s voice called out over the sound of cracking air and bones.

“Will! Get back down here and hold still so I can fix your eyes! He’s not doing anything!”

Well, that’s embarrassing, Will thought, letting go of the courtyard wall and sliding back down.

It was strange navigating by air pressure against his skin crossed with his mental map of the environment, but he wasn’t doing a bad job.

I should practice this.

Will could feel Charnesa approach and hold her hands up to his temples. A flash of Charge later, Will could see again.

Ghoul was splattered up against the far wall, his body reassembling itself.

The undead gave them a thumb’s-up.

“Sorry.” Will said with a guilty nod. “Reflex.”

“No, no, it’s a good reflex to have,” Ghoul rasped, spitting out a bit of black ichor. “You do owe me a new set of clothes, though.

“That’s fair.” Will said, approaching the Lord as he rose to his feet. “So what the Abyss did you just do? It looked like the entire world went white, and I couldn’t see. It didn’t have anything to do with air at all.”

“Oh, it has something to do with air. Have you ever seen a mirage? Where you can see the stars above on the ground?”

Will grew up in the desert near The Tower, so of course he’d seen them.

“Yeah?”

“That effect is a result of layers of air that have different densities causing refraction. The layering trick you invented to reinforce a missile of air could also be used to bend light under the right circumstances. There are other applications I think we can learn like cavitation and vacuums, but we’ll start with light, ‘cause it’s the most interesting to me, personally.”

“…What?” Will cocked his head to the side.

“…Do you know what refraction and lensing is?”

Will shook his head.

“…How much school did you have?”

“Like, real school?”

“…Shit.” Ghoul motioned to Badur. “You, logistician, get him a notebook and writing materials. You,” Ghoul pointed at a nearby undead. “Get me my magnifying glass. And you, get the chalkboard out of storage. I’m gonna need a straightedge, too…”

Will watched the people hustle to obey before peering back at ghoul, who was rubbing his flaking chin.

“You didn’t really answer my question. What the Abyss did you do?”

Ghoul glanced back at him. “I made a gigantic lens out of air that focused the light of the sun directly into your eyes.”

“But…it looked like the light was white, not purple.” Will said, glancing up at the faint purple sun. “And it was way bigger than the sun. It was the only thing I could see.”

“Light looks white when it’s burning your retinas out.” Ghoul said with a dismissive wave. A moment later, an undead arrived with a strange green board on wheels, while another arrived with a chair.

“Take a seat.” Ghoul said, picking up a ruler and chalk and began drawing straight lines originating from a point. “I can explain why it looked huge. This is also relevant to how the cantrip will work.”

Will glanced down at the seat.

“Can I…put my clothes back on first?”

“Of course.”

“Awww…” Bee grumbled and splintered off from the group of observers as Will put on his pants and shirt.

“Can I sit in?” Loth asked. “This is an interesting topic.”

“Help yourself,” Ghoul said, bringing in an extra chair before drawing an eyeball at the other end of the green board.

“This is your eye.” He tapped his straightedge on the eyeball, then traced a single line back from the eyeball until it hit the circle with all the lines coming out of it.

“This is the light source. Do you see how only this one line hits your eye?”

Will nodded.

“This represents how much light generated by an object is actually hitting your eye. A very very small percentage. The vast majority of light is scattered into the environment, usually providing ambient light as it reflects off surfaces.”

Will was following so far.

“What I did was this…”

This content has been unlawfully taken from Royal Road; report any instances of this story if found elsewhere.

Ghoul pulled out a rag and wiped away a good portion of the lines before carefully drawing an oval shape.

“This is a lens.” Ghoul said. re-drawing the lines where they intersected with the oval, with the lines turning inward and converging on the eye. “It took all that light generated by the light source and bent it in-flight to turn towards your eye. Since your eye saw light coming from the source from all these directions…it appeared to be huge.”

Will understood why it looked big, but didn’t understand how this lens thing could bend light, and he said as much.

For illustration, Will made an oval of hardened air, but it didn’t bend the light no matter which way he turned it.

“So the missing ingredient is the density of the medium the light travels through. Light is already travelling through the air, which has its own density, and that air is changing the path of light, we just don’t experience it because we’re inside it, not observing from outside. This is why fish seem to be in a slightly different location than they actually are, because water has a different density.”

Will perked up at that. He’d experienced that before.

“Look at this,” Ghoul said, accepting a magnifying glass from one of his undead. “This glass magnifying glass is able to effectively bend light because the surrounding medium is air, and the glass is far, far more dense than the air around it. Hypothetically, if the atmosphere were made of glass, this trinket would do nothing, because there would be no difference in density between this and the atmosphere.”

“I…think I get it.” Will said. “What’s High-pathetic mean?”

“In this case? An Imagined possibility.” Loth said.

“And Atmosphere?”

“The air.” Loth replied.

“Why not just say the air?” Will asked

“It means the air around the entire planet. It’s a bigger, more encompassing thing.”

“Huh.”

“Here, get a feel for it.” Ghoul said, handing Will the magnifying glass.

Will had only seen a handful of them, in jeweler’s tools, in the offices of the rich and famous. Notaries. People who looked at small things for a living. Not something he’d ever really thought about. It felt weird to be holding one himself.