"Have you more books?"

"Not with me. I occasionally come upon them, however."

"I want to scan them all."

"Then the next time I pass this way I will bring you another."

"When will that be?"

"That I cannot say, great Frost. It will be when it will be."

"What do _you_ know of Man?" asked Frost.

"Much," replied Mordel. "Many things. Someday when I have more time Iwill speak to you of Him. I must go now. You will not try to detain me?"

"No. You have done no harm. If you must go now, go. But come back."

"I shall indeed, mighty Frost."

And he closed his turret and rolled off toward the other horizon.

For ninety years, Frost considered the ways of human physiology and waited.

The day that Mordel returned he brought with him _An Outline ofHistory_ and _A Shropshire Lad_.

Frost scanned them both, then he turned his attention to Mordel.

"Have you time to impart information?"

"Yes," said Mordel. "What do you wish to know?"

"The nature of Man."

"Man," said Mordel, "possessed a basically incomprehensible nature. Ican illustrate it, though: He did not know measurement."

"Of course He knew measurement," said Frost, "or He could never havebuilt machines."

"I did not say that He could not measure," said Mordel, "but that Hedid not _know_ measurement, which is a different thing altogether."

"Clarify."

Mordel drove a shaft of metal downward into the snow.

He retracted it, raised it, held up a piece of ice.

"Regard this piece of ice, mighty Frost. You can tell me itscomposition, dimensions, weight, temperature. A Man could not look at itand do that. A Man could make toold which would tell Him these things,but He still would not _know_ measurement as you know it. What He wouldknow of it, though, is a thing that you cannot know."