Would some Earth telescope be able to see us? I doubted it. The pinpoint of the _Planetara's_ infinitesimal bulk would be beyond them. Long silences, broken only by the faint hiss and murmur of Snap's instruments. "Shall I try the 'graphs, Miko?" "Yes." I helped him with the spectroheliograph. At every level the plates showed us nothing save the scarred and pitted Moon-surface. We worked for an hour. There was nothing. Bleak cold night on the Moon here beneath us. A touch of fading sunlight upon the Apennines. Up near the South Pole, Tycho with its radiating open rills stood like a grim dark maw. Miko bent over a plate. "Something here? Is there?" An abnormality upon the frowning ragged cliffs of Tycho? We thought so. But then it seemed not. * * * * * Another hour. No signal came from Earth. If Snap's calls were getting through we had no evidence of it. Abruptly Miko strode at me from across the room. I went cold and tense; Moa shifted, alert to my every movement. But Miko was not interested in me. A sweep of his clenched fist knocked the ultra-violet sender and its coils and mirrors in a tinkling crash to the grid at my feet. "We don't need that, whatever it is!" He rubbed his knuckles where the violet waves had tinged them, and turned grimly back to Snap. "Where are your Gamma ray mirrors? If the treasure is exposed--" This Martian's knowledge was far greater than we believed. He grinned sardonically at Anita. "If our treasure is on this hemisphere, Prince, we should pick up Gamma rays? Don't you think so? Or is Grantline so cautious it will all be protected?" Anita spoke in a careful, throaty drawl. "The Gamma rays came plain enough when we passed here on the way out." "You should know," grinned Miko. "An expert eavesdropper, Prince--I will say that for you. Come Dean, try something else. By God, if Grantline does not signal us, I will be likely to blame you--my patience is shortening. Shall we go closer, Haljan?" "I don't think it would help," I said. He nodded. "Perhaps not. Are we checked?" "Yes." We were poised, very nearly motionless. "If you wish an advance, I can ring it. But we need a surface destination now." "True, Haljan." He stood thinking. "Would a zed-ray penetrate those crater-cliffs? Tycho, for instance, at this angle?"[B] "It might," Snap agreed. "You think he may be on the Northern inner side of Tycho?" "He may be anywhere," said Miko shortly. "If you think that," Snap persisted, "suppose we swing the _Planetara_ over the South Pole. Tycho, viewed from there--" "And take another quarter-day of time?" Miko sneered. "Flash on your zed-ray; help him hook it up, Haljan." [B] An allusion to the use of the zed-ray light for making spectro-photographs of what might be behind obscuring rock masses, similar to the old-style X-ray. * * * * *