Crawford Bell glanced at his watch. "Here's where I earn my money." His fingers tapped the computer keys.

MacFarland's stomach tingled. He wanted to jump out of the car and push the toga clad men aside with his bare hands. Days of frustration were reaching a climax.

He switched on the mike. "Sabo, we'll have to stand toe to toe with those boys and slug it out. I want you to guard our rear. Have your men put a tight line behind us. Don't let the crowd get near the convoy."

They halted in front of the airport gate, less than twenty feet from the enemy line. The other vehicles pulled up beside them.

The scientists parked on his left. "You've done a good job," Doctor Warren said, "but it looks like we're not going any further."

"Did you bring machine guns and clubs?" Doctor Umbana asked. "If you didn't let's go home and get some sleep."

MacFarland stood up. "Gentlemen, we've got half an hour and a good crew of technicians." The line of Belderkans looked grim and unmoving. Their black faces gleamed in the light from the helicopter.

"Now," Crawford Bell said.

Again, the awful sound rose from the noisemaker. MacFarland tried to look indifferent but after the first seconds he grabbed his ears with his hands. It was the scream of pain and madness and the evil thing beyond the campfire. The faces of the Belderkans distorted with anguish.

Using noise was tricky. How hard did the air molecules have to strike the ears or how painful did the noise have to be, before sound became physical violence? The noise selected by the computer was supposed to be psychologically, but not physically, uncomfortable.