“Was the phaen an illusion, then?”

“In no sense.”

“Well, explain quickly, then, what has taken place.  I seem to be going mad.”

“There’s nothing unintelligible in it, if you’ll only listen calmly.  The phaen belonged, body and soul, to the outside, visible world—­to Faceny.  This underworld is not Faceny’s world, but Thire’s, and Faceny’s creatures cannot breathe its atmosphere.  As this applies not only to whole bodies, but even to the last particles of bodies, the phaen has dissolved into Nothingness.”

“But don’t you and I belong to the outside world too?”

“We belong to all three worlds.”

“What three worlds—­what do you mean?”

“There are three worlds,” said Corpang composedly.  “The first is
Faceny’s, the second is Amfuse’s, the third is Thire’s.  From him
Threal gets it name.”

“But this is mere nomenclature.  In what sense are there three worlds?”

Corpang passed his hand over his forehead.  “All this we can discuss as we go along.  It’s a torment to me to be standing still.”

Maskull stared again at the spot where Leehallfae’s body had lain, quite bewildered at the extraordinary disappearance.  He could scarcely tear himself away from the place, so mysterious was it.  Not until Corpang called to him a second time did he make up his mind to follow him.

They set off from the rock wall straight across the airlit plain, directing their course toward the nearest trees.  The subdued light, the absence of shadows, the massive shafts, springing grey-white out of the jetlike ground, the fantastic trees, the absence of a sky, the deathly silence, the knowledge that he was underground—­the combination of all these things predisposed Maskull’s mind to mysticism, and he prepared himself with some anxiety to hear Corpang’s explanation of the land and its wonders.  He already began to grasp that the reality of the outside world and the reality of this world were two quite different things.

“In what sense are there three worlds?” he demanded, repeating his former question.

Corpang smote the end of his staff on the ground.  “First of all, Maskull, what is your motive for asking?  If it’s mere intellectual curiosity, tell me, for we mustn’t play with awful matters.”

“No, it isn’t that,” said Maskull slowly.  “I’m not a student.  My journey is no holiday tour.”

“Isn’t there blood on your soul?” asked Corpang, eying him intently.

The blood rose steadily to Maskull’s face, but in that light it caused it to appear black.

“Unfortunately there is, and not a little.”

The other’s face was all wrinkles, but he made no comment.

“And so you see,” went on Maskull, with a short laugh, “I’m in the very best condition for receiving your instruction.”

Corpang still paused.  “Underneath your crimes I see a man,” he said, after a few minutes.  “On that account, and because we are commanded to help one another, I won’t leave you at present, though I little thought to be walking with a murderer....  Now to your question....  Whatever a man sees with his eyes, Maskull, he sees in three ways—­ length, breadth, depth.  Length is existence, breadth is relation, depth is feeling.”