The tower and the ruined city had taken his attention from the business of flying. Now suddenly he was startled by the rapid-fire of his scintillometer. It was recording .400 milliroentgens an hour--unendurable! "The dead," said O'Hara, "were reaching out for me. They wanted me, an alien probing through the skies above their tomb. And I felt their hostility, as if a shower of warheads had come roaring up. The contamination was as murderous as any warheads would have been." The tautness of his steep climb skyward and sharp swerve back toward the spinal cord of the continent precluded any further observations. He was now acutely alarmed. He expected at any moment to discover upon his body the raw violence of radioactive burns, he anticipated bleeding and there was at the hinges of his jaws a definite sensation of nausea. Yet moments passed without development of these symptoms. The nausea abated. He was not stricken yet, or if he was, the effects were not yet obvious. And this raised possibilities of conditioning to the contamination that had never been explored--that no one, in the world he knew, had dared to explore. It might yet prove to be that man could exist in these extremes of radioactivity. Large mottled patches now were appearing between the pale blue-white stretches of endless snow. The mountain peaks and the high plateaus still presented their heavily drifted appearance, but in the deeper valleys an occasional ice-free river twisted, seeking its outlet either toward the east or west--the east, O'Hara remembered, would lead to the intricate arterial system that would at last merge into the Mississippi River, the continental sewer that dumped its burden of silt and debris into the swampland delta of--what was it? Louisiana? The whole once-familiar pattern of maps he had intensely studied as a child now was coming back vividly--the two mountain systems, Appalachian and Rockies, the great valley of the Mississippi, the Atlantic and Pacific coastlands, the spider web of fabulous cities, names like New York and Washington, Chicago and Kansas City, Los Angeles and San Francisco, and somewhere in these Rockies which he was now following were--or had been--Salt Lake City and Denver. There was a definite excitement in these names that for O'Hara rolled back the drab present to that glittering past, when the word _tomorrow_ had meant more than a repetition of today.