“But that makes no sense…!” Chert began, then Opal caught his eye. “Apologies. Please continue.”

“That does not mean the world is made of water,” Chaven explained. “Let me explain. Just off the coast of my homeland Ulos in the south there is a cold current that moves through the water—cold enough to be felt with the hand, and even of a slightly different color than the rest of the Hesperian Ocean. This cold current sweeps down from the forbidden lands north of Settland, rushes south past Perikal and the Ulosian coast, then curves back out to sea again, finally disappearing in the waters off the western coast of distant Xand. Does that water travel through a clay pipe, like a Hierosoline water-channel bringing water hundreds of miles to the city? No. It passes through other water—it is water itself—but it retains its characteristic chill and color.

“This, says the School of Phelsas, is the nature of the worlds, our world, the world of the gods, and others. They touch, they flow through each other, but they retain that which makes them what they are. They inhabit almost the same place, but they are not the same thing, and most of the time there is no crossing over from one to another. Most of the time, one cannot even perceive the other.”

Chert shook his head. “Strange. But where do mirrors fit into this?”

For once in the conversation, Opal did not seem to find him a waste of breath. “Yes, please, Doctor. What about the mirrors?”

Their guest shrugged in discomfort. Even after several days, it was still strange to see him here in their front room. Chert knew that Chaven was not particularly large for one of the big folk, but in this setting he loomed like a mountain. “You do not need to call me ‘Doctor,’ Mistress Blue Quartz.”

“Opal! Call me Opal.”

“Well. Chaven, then.” He smiled a little. “Very well. Ximander’s Book tells that mirror-lore is the third great gift because it allows men to glimpse these other worlds that travel as close to us as our own shadows. Just as an ordinary mirror bounces back the vision that is before it, so too can a special mirror be constructed and employed that will send back visions of…other places.” He paused for a moment, as if considering what he was about to say very carefully. In the silence, Opal spoke up.

“It has to be a…special mirror?”

“In most cases and for most mirror-scrying, yes.” Chaven looked at her in surprise. “You have heard something of this?”

“No, no.” Opal shook her head. “Please go on. No, wait. Let me quickly look in on the boy.” She got up and left the room, leaving Chert and Chaven to sip their tea. The blueroot had helped a little: Chert no longer felt as though he might fall onto his face at any moment.

Opal returned and Chaven took a breath. “As I said, I will not bore you with too much mirror-lore, which is complicated and full of disputations—just learning and understanding some of the disagreements between the Phelsaians and the Captrosophist Order in Tessis could take years. And of course the Trigonate church has considered the whole science blasphemous for centuries. In bad times, men have burned for mirrors.” As he said this, Chaven faltered a little. “Perhaps now I know why.”