can be heard by humans. They were developed, built, and financed by graduate mutants. They broadcast on different frequencies that we have determined most effective in upsetting the equilibrium of unstable chemical compounds.”

“Do you mean,” asked Hoshawk, “that you are going to try to detonate the explosives carried by Forgacs’ planes?”

“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