"But—you don't want us to bring the sledge...."
"And we haven't—" this was Holmes—"we haven't enough air to get back! How can we do it, sir?"
McCauley relaxed in his small cubbyhole of an office. Very privately he drew a breath of relief. But his tone remained stern.
"You will head for Repeater One. If you remember, my voice goes from the base here to Repeater One where it is relayed to Repeater Two. If I chose the proper frequency it would go on through Three and Four to Farside. Can you think of any advantage in being at Repeater One instead of Two?"
A long pause. Then Holmes' voice, dubious:
"It's nearer the base, sir. No more than three hours' travel, if that much. We could make it on one tank of air apiece, sir, and have the extra one for margin. We could make it to base from there, sir, if we were there. But we're not, and it's three hours' travel from here! We'd get there...."
"You would get there?" demanded McCauley ominously. "Or you will get there?"
"Will, sir." But the young officer's voice was bewildered.
"For your information," said McCauley curtly, "the Repeater One relay unit is exactly like the relay unit at Repeater Two. I may add that it is in bright sunshine, but will not be so indefinitely."—This was because McCauley remembered an air tank which had lain in shadow until its metal shivered brittlely when struck and the air inside it was a liquid. "It was carried to its position and mounted exactly as the relay for Repeater Two was. Now figure it out for yourself! If you still don't understand when you get to it, call me from there. Now get moving! Sunset's not far away."
He clicked off his microphone, but left the receiving unit on. The relay at Repeater Two would pick up suit-radio speech and relay it back, the pickup being from its all-direction antennae. McCauley heard mumblings. Then, very distinctly, Holmes spoke.