Incidentally, I have forgotten the most important thing of all. Remember that Donovan’s dominating idea was to prove to me, and to the world, that he had been in the Cretaceous and hobnobbed with its flora and fauna. He was a physicist by inclination, and had the physicist’s flair for ingenious proofs. Before leaving, he loaded a lead cube with three quartz quills of pure radium chloride that he had been using in a previous experiment, and locked the whole thing up in a steel box.

He had boarded the kettle in the 575th Century, the base of operations assigned to him two years earlier. At the time the 575th had been the farthest upwhen he had ever traveled. Now he was moving upwhen to the 2456th Century.