"The line AB represents the time line of the earth and the line CD
represents the time line of any other planet X. The two lines are
parallel. E represents the earth--_Now_, and F the _Now_ on planet X. A
line connecting the two is perpendicular to both AB and CD. Supposing
we should travel from F to a point G, a _Now_ in the earth's past. If
we connect F and G we would have a right triangle GEF. The hypothenuse
GF would be the square root of GE squared plus EF squared."
"There is nothing mathematically implausible in that," I said.
"There is nothing implausible, yet to determine the exact distance from
G to F is in most cases impossible. Unless the distances involved are
of the proper ratio, say, 4 and 5, the line GF becomes an irrational
number, of which it is impossible to find the exact value. Supposing
the distance from E to F was one light-year and the distance from G
to E, one year. Then GF would be the square root of one squared plus
one squared, or the square root of two. Because we are dealing with
such immense distances and because even the smallest decimal point of
error might lead to disastrous results, we cannot attempt time travel
unless we know the exact value of the square root of two, or any other
irrational number."
As Trella finished speaking there was a coughing hum and the translator
appeared in the room, containing the unharmed guinea pig and a copy of
the _Rihlon Gazette_ for Aug. 3rd, which was this day.
"Do you believe me?" she cried gleefully, waving the paper over her
head.
It was quite convincing, I admitted.
"Now I am going to make a trip in the translator!"
"You!"
It was the beginning of a long argument. There was danger in the trip,
I told her, and Trella had come to mean a great deal to me. She scoffed
at my fears and told me that if I didn't care to witness the first
translation of man to another planet in another star system she would
do it when I wasn't there.
Of course, no man can win an argument with a woman.
Trella climbed into the translator.
I closed the opening. Her hand rose to the switch that operated the
mechanism from inside the tube. She smiled and her lips moved in a
cheerful good-by. Then she touched the switch.
The indicator on the dial crept upward toward the gold star.
Suddenly the unexpected occurred.
The door of the laboratory opened. Trella had forgotten to lock the
door when we entered the room.
As I heard the noise, I turned and saw Gustav Keeshwar leveling a gun
toward the helpless young woman in the glass tube.