Talliaferro found himself insensibly drifting back in time. They had not changed much. Nor, he thought, had he himself. They were all ten years older, of course. Ryger had put on some weight and Kaunas’s thin face had grown a bit leathery, but he would have recognized either if he had met him without warning.

He said, “I don’t think it’s Earth getting us. Let’s face it.”

Kaunas looked up sharply. He was a little fellow with quick, nervous movements of his hands. He habitually wore clothes that looked a shade too large for him.

He said, “Villiers! I know. I think about him sometimes.” Then, with an air of desperation, “I got a letter from him.”

Ryger sat upright, his olive complexion darkening further and said with energy, “You did? When?”

“A month ago.”

Ryger turned to Talliaferro. “How about you?”

Talliaferro blinked placidly and nodded.

Ryger said, “He’s gone crazy. He claims he’s discovered a practical method of mass-transference through space.

—He told you two also?—That’s it, then. He was always a little bent. Now he’s broken.”

He rubbed his nose fiercely and Talliaferro thought of the day Villiers had broken it.

For ten years, Villiers had haunted them like the vague shadow of a guilt that wasn’t really theirs. They had gone through their graduate work together, four picked and dedicated men being trained for a profession that had reached new heights in this age of interplanetary travel.

The Observatories were opening on the other worlds, surrounded by vacuum, unblurred by air.

There was the Lunar Observatory, from which Earth and the inner planets could be studied; a silent world in whose sky the home-planet hung suspended.

Mercury Observatory, closest to the sun, perched at Mercury’s north pole, where the terminator moved scarcely at all, and the sun was fixed on the horizon and could be studied in the minutest detail.