l perished from the earth long ago! I'm the
last man on earth!"

"It is a dead world now," interjected 25X-987.

"Of course," elucidated the mathematician, "those last few million years
are much shorter than the ones in which you lived. The earth's orbit is
of less diameter and its speed of revolution is greatly increased, due
to its proximity to the cooling sun. I should say that your year was
some four times as long as the time in which it now takes your old
planet to circumnavigate the sun.

"How many days were there in your year?"

"Three hundred and sixty-five."

"The planet has now ceased rotating entirely."

"Seems queer that your rocket satellite should avoid the meteors so
long," observed 459C-79, the mathematician.

"Automatic radium repulsion rays," explained the professor.

"The very rays which kept us from approaching your rocket," stated
25X-987, "until we neutralized them."

"You died and were shot out into space long before any life occurred on
Zor," soliloquized one of the machine men. "Our people had not yet even
been born when yours had probably disappeared entirely from the face of
the earth."

"Hearken to 72N-4783," said 25X-987, "he is our philosopher, and he just
loves to dwell on the past life of Zor when we were flesh and blood
creatures with the threat of death hanging always over our heads. At
that time, like the life you knew, we were born, we lived and died, all
within a very short time, comparatively."

"Of course, time has come to mean nothing to us, especially when we are
out in space," observed 72N-4783. "We never keep track of it on our
expeditions, though back in Zor such accounts are accurately kept. By
the way, do you know how long we stood here while you recounted to us
the history of your planet? Our machine bodies never get tired, you
know."

* * * * *

"Well," ruminated Professor Jameson, giving a generous allowance of
time. "I should say about a half a day, although it seemed scarcely as
long as that."

"We listened to you for four days," replied 72N-4783.

Professor Jameson was really aghast.

"Really, I hadn't meant to be such a bore," he apologized.

"That is nothing," replied the other. "Your story was interesting, and
if it had been twice as long, it would not have mattered, nor would it
have seemed any longer. Time is merely relative, and in space actual
time does not exist at all, any more than your forty million years'