A man cast away on a desert isle could always live for hope, but here there was no hope. A Robinson Crusoe was separated from his fellow-humans by, at the most, a few thousand miles. Here they were separated by a hundred and fifty thousand years.

Wes Adams was the lucky one so far. Even playing his thousand-to-one shot, he still held tightly to a purpose, feeble as it might be—the hope that he could repair the time machine.

We don't need to watch him now, thought Hudson. The time we'll have to watch is when he is forced to admit he can't fix the machine.

And both Hudson and Cooper had been kept sane enough, for there had been the cabin to be built and the winter's supply of wood to cut and the hunting to be done.

But then there would come a time when all the chores were finished and there was nothing left to do.

"You ready to go?" asked Cooper.

"Sure. All rested now," said Hudson.

They hoisted the pole to their shoulders and started off again.

Hudson had lain awake nights thinking of it and all the thoughts had been dead ends.

One could write a natural history of the Pleistocene, complete with photographs and sketches, and it would be a pointless thing to do, because no future scientist would ever have a chance to read it.