s
flickered again with that strange, mad light--"I am a scientist! I
have left my age behind me for a time; I have done what no other human
being has ever done: I have gone centuries into the future!"

"I--I do not understand." Could he, after all, be a madman? "How can
a man leave his own age and travel ahead to another?"

"Even in this age of yours they have not discovered that secret?"
Harbauer exulted. "You travel the Universe, I gather, and yet your
scientists have not yet learned to move in time? Listen! Let me
explain to you how simple the theory is.

* * * * *

"I take it you are an intelligent man; your uniform and its insignia
would seem to indicate a degree of rank. Am I correct?"

"I am John Hanson, Commander of the _Ertak_, of the Special Patrol
Service," I informed him.

"Then you will be capable of grasping, in part at least, what I have
to tell you. It is really not so complex. Time is a river, flowing
steadily, powerful, at a fixed rate of speed. It sweeps the whole
Universe along on its bosom at that same speed. That is my conception
of it; is it clear to you?"

"I should think," I replied, "that the Universe is more like a great
rock in the middle of your stream of time, that stands motionless
while the minutes, the hours, and the days roll by."

"No! The Universe travels on the breast of the current of time. It
leaves yesterday behind, and sweeps on towards to-morrow. It has
always been so until I challenged this so-called immutable law. I said
to myself, why should a man be a helpless stick upon the stream of
time? Why need he be borne on this slow current at the same speed? Why
cannot he do as a man in a boat, paddle backwards or forwards; back to
a point already passed; ahead, faster than the current, to a point
that, drifting, he would not reach so soon? In other words, why can he
not slip back through time to yesterday; or ahead to to-morrow? And if
to to-morrow, why not to next year, next century?

* * * * *

"These are the questions I asked myself. Other men have asked
themselves the same questions, I know; they were not new.
But,"--Harbauer drew himself far forward in his chair, and leaned
close to me, almost as though he prepared himself to spring--"no other
man ever found the answer! That remained for me.

"I was not entirely correct, of course. I found that one could not go
back in time. The current was against one