on a little way in silence, arguing silently with
himself as to the correctness of these premises. Then he began aloud
again:

"Yes, I think that's about right. And now, suppose that such a being
became endowed with the natural senses, one by one. It would go through
all the processes of the physical and mental evolution of humanity until
it reached the highest of human attributes--the ability to think, and
therefore to reason. In other words, from a merely living organism it
would, in the old Scriptural language, have become a living soul. That
is, obviously, what the words in Genesis were really intended to mean.
It would then become capable of development, of proceeding from the
partly-known to the more fully known, until, granted perfect physical
and mental health, it reached what are generally called the limits of
human knowledge."

The Professor's thumb and finger went up to his chin again. He walked
another two or three hundred yards in silence; then he recommenced his
spoken argument with himself:

"Limits of human knowledge? Yes, that sounds all very well in ordinary
language, but are there any? Who was it said that a man trying to reach
those limits was like the child who saw a rainbow for the first time,
and started out to find the place where it rested? The simile is not
bad, not by any means. Just in the same way, we try to imagine the
limits of time and space, and we can't do it. Only infinity of space and
duration are possible, and yet we can't grasp them; still, they are the
only possible states in which we can exist. And now, as I have had a
glimpse of the past, I wonder what this place would be like in ten
thousand years?

"Good heavens, how cold it is!" He shivered, and buttoned up his coat,
and continued, looking about him on the vast snow-field dotted with
hummocks of ice which lay bleak and lifeless about him: "Ah, I suppose
either the Gulf Stream has got diverted, or the earth's axis has shifted
and we are in another glacial epoch.

"WE!"

Again the shock of utter isolation struck him, but it seemed to hit him
harder this time. The world that he had been born in lay ten thousand
years behind him. For all he knew, he might be standing upon what was
now the earth's North Pole. Civilisation, as he had known it, might have
been wiped off the face of the earth, and the remnants of humanity flung
back into savagery. He looked up at the sun, and saw that it was almost
exactly where it had been, a