"His planes, and anything else that carries them. We have analyzed samples of his explosives to determine the critical frequency of each. These nineteen stations cover the country. Any known explosive in the continental United States will be detonated when these stations go into operation." "What if Forgacs has some unknown explosive?" Wadsworth was solemn. "We take that chance," he said. "But the range of possible explosive combinations is well known, and something entirely different is unlikely. At any rate--" "They're starting to drop bombs!" Hoshawk said. * * * * * The President watched the red glow around Kansas City. His face was taut. "There will be many cities destroyed," he said. "But we must wait for all of Forgacs' equipment to be within our continental limits. It must all be destroyed at once." "But the bombers are in action," said Hoshawk. "Denver is getting it now." Wadsworth's eyes were on the coastlines. "It will be twenty minutes at least before we can open the transmitters. We may lose most of our cities by that time, but there is nothing we can do." The red glows began to spread. Dallas and Fort Worth, New Orleans, Atlanta, Miami, San Diego and Los Angeles, San Francisco, Portland and Seattle. The bombers were systematically destroying America's population centers. And still Wadsworth waited. He sat tense before the Map, watching the endless stream of lights come from the sea. But they were beginning to end. Many were far inland, attacking the smaller cities, cleaning up the big ones. "The bombers won't be destroyed," said Hoshawk, "if they've already dropped their bombs." "I think they will, for all practical purposes," said the President. "Their ammunition, their signal flares--everything explosive will be detonated." "How can you cover them all at once?" "There are over nine hundred frequencies--but we don't know that they will be enough," Jeffrey pointed out gravely. "We can only hope." Hoshawk couldn't stand still any longer. He paced the floor before the Map. "Every city in America of more than a hundred thousand is gone--obliterated," he said tonelessly. "Can't we ever--" "Wait!" The President was alert. "The last line of flame-throwers is coming on land." He pointed to the black dots streaming up on the west coast. He spoke into the audio transmitter. He didn't bother with the scrambler now. "Sonic stations on. Emergency force. Sonic stations on. Emergency force. Situation critical." He pointed to the Map and sat back. Within a few seconds the purple lights began to flash intermittently. "They're on," said the President. "But it will take a few minutes for them to reach full intensity. The sonic devices operate at high speeds--some at two hundred thousand r.p.m." Hoshawk watched, almost without breathing. For the first time he was aware that the forty statesmen of the Western Hemisphere were watching through the glass windows of the Chamber.