Short Story
Hindsight
- by Jack Williamson
- Astounding, May 1940
Years ago, engineer Bill Webster abandoned Earth for the employ of the piratical Astrarch far beyond the orbit of Mars; now the Astrarch is aiming the final blow at a defeated Earth, and Bill wonders whether the gun sights he invented can spot—and change!—events in the past. —Michael Main
The tracer fields are following all the world lines that intersected at the battle, back across the months and years. The analyzers will isolate the smallest—hence most easily altered—essential factor.
