"Enough! _Are_ you an agent of Divcom?"
"I am Mordel."
"Why are you here?"
"I was passing this way and, as I said, we share a common interest, mighty Frost. Knowing you to be a fellow antiquarian, I have brought a things which you might care to see."
"What is that?"
"A book."
"Show me."
The turret opened, revealing the book upon a wide shelf.
Frost dilated a small opening and extended an optical scanner on a long jointed stalk.
"How could it have been so perfectly peserved?" he asked.
"It was stored against time and corruption in the place where I found it."
"Where was that?"
"Far from here. Beyond your hemisphere."
"_Human Physiology," Frost read. "I wish to scan it."
"Very well. I will riffle the pages for you."
He did so.
After he had finished, Frost raised his eyestalk and regarded Mordel through it.
"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 I will 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 of History_ 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. I can illustrate it, though: He did not know measurement."
"Of course He knew measurement," said Frost, "or He could never have built machines."
"I did not say that He could not measure," said Mordel, "but that He did 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 its composition, dimensions, weight, temperature. A Man could not look at it and 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 would know of it, though, is a thing that you cannot know."
"What is that?"
"That it is cold," said Mordel and tossed it away.
"'Cold' is a relative term."
"Yes Relative to Man."
"But if I were aware of the point on a temperature scale below which an object is cold to a Man and above which it is not, then I, too, would know cold."
"No," said Mordel, "you would possess another measurement. 'Cold' is a sensation predicated upon human physiology."
"But given sufficient data I could obtain the conversion factor which would make me aware of the condition of matter called 'cold'."
"Aware of its existence, but not of the thing itself."