"... rimaldi Ba...." Silence, then suddenly: "Hello!"

It was Holmes' voice. McCauley recognized it.

"Holmes!" he said curtly. "You two fools have committed suicide! You dropped one air tank off the sledge. Remember? That meant that only one of you could get back, and you and Kent could decide later which one it would be. But Kent kicked an air tank off, too! Now who's coming back?"

There was a startled silence.

"You heard me!" said McCauley savagely. "There were three tanks on that sledge. They'd bring you both back with air to spare. But you threw one away, and Kent threw one away, and so there's one left. It's six hours' travel back to here, and you've air for two men for four and a half!"

Again silence. McCauley could envision the scene at Repeater Two, to which his voice was transmitted by precisely the system of beam relay used on Earth to carry telephone messages across continents without wires. There would be two bulky, space-suited figures atop an irregularly level space from which the ground fell away on every side, a drop of thousands of feet. They would be in glaring sunlight from the lowest of low-hanging suns. Where it struck the metal of their space armor they would glitter blindingly. Where there was shadow, there would be the blackness of the pit. Overhead there stretched a black sky with a thousand million stars, and around and below them there would be long, angular, parallel ribbons of shadow with sharply defined sides and with beginnings but no ends. And there would be the moon sledge with the relay built solidly upon it, its runners chocked with stony debris so it would not slide or topple. There would be the two bowl-shaped beam reflectors, one pointing back to Repeater One—itself a moon sledge wedged in place upon a mountain—and the other to remoteness and to wildness and to night.

"You could come back as you went," said McCauley. "You could bring back the sledge, breathing air from its tanks on the trip. But if you did that, Farside would be out of communication during the coming night. That would have to be explained."

Again it seemed that he could see the faraway, motionless figures of the two men listening over their suit radios to the voice twice relayed before it could reach their ears.

"I would have to explain," said McCauley grimly, "that Lieutenants Kent and Holmes intended to murder each other, and each one threw away an air tank he expected the other man to use—but he expected to have plenty of air for himself! I would have to explain that Farside was isolated because two would-be murderers had outsmarted themselves and didn't have the guts to face the consequences!"

Kent's voice came from a speaker. He spoke from that distant mountain peak toward which darkness crept steadily.