Also appearing in the first ever Probability Zero column (along with de Camp’s story, listed above, and a story by Malcolm Jameson) is Carnell’s tale of a group of science fiction authors who explore the consequences of a simple time machine that can be built from radio parts, but can take the traveler only into the future.
Yes, they were practically all here, thought Doc Smith, as his gaze moved from one to another of the circle. Williamson, Miller, Hubbard, Bond, McClary, Rocklynne, Heinlein and MacDonald, and many others who had once written about the mysteries of time travel—so many hundreds of years ago now.

Variants

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  1. “Time Marches On” by Ted Carnell, Astounding, August 1942.
    2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . written by Ted Carnell