Millions of years in the distant future, a posthuman scientist is attempting to build a time machine and tests it by sending a box with a hastily gathered batch of educational toys into the past. When the box fails to return, he constructs another and tests it the same way, but it also fails to return. Believing the entire experiment to be a failure, he discontinues his efforts and gives up on time machines. The first box arrives in the middle of the twentieth century and the second in the latter part of the nineteenth century. Both have had their time-travel circuitry irreparably damaged by the journey.
Originally published in the February 1943 issue of "Astounding Science Fiction Magazine.
Novelette, Classic science fiction, the basis for the film "The Last Mimsy"