"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.
At that instant purple glows began to surround the green lights, starting on the east coast of Florida and spreading upward.
"Amphibian submarines," whispered the President. "Their aerial torpedoes are exploding!"
"And up around the Great Lakes," said Hoshawk. "There it's amphibian tanks."
The President sat, and watched. The glows spread. They absorbed flame-throwers, tractors, mine-heavers. The Map of America was a clustered mass of lights, with the purple glow beginning to consume everything in its reach.