"You may see one today," Kynes said. "Wherever there is spice, there are worms."

"Always?" Halleck asked.

"Always."

"Is there relationship between worm and spice?" the Duke asked.

Kynes turned and Paul saw the pursed lips as the man spoke. "They defend spice sands. Each worm has a--territory. As to the spice . . . who knows? Worm specimens we've examined lead us to suspect complicated chemical interchanges within them. We find traces of hydrochloric acid in the ducts, more complicated acid forms elsewhere. I'll give you my monograph on the subject."

"And a shield's no defense?" the Duke asked.

"Shields!" Kynes sneered. "Activate a shield within the worm zone and you seal your fate. Worms ignore territory lines, come from far around to attack a shield. No man wearing a shield has ever survived such attack."

"How are worms taken, then?"

"High voltage electrical shock applied separately to each ring segment is the only known way of killing and preserving an entire worm," Kynes said. "They can be stunned and shattered by explosives, but each ring segment has a life of its own. Barring atomics, I know of no explosive powerful enough to destroy a large worm entirely. They're incredibly tough."

"Why hasn't an effort been made to wipe them out?" Paul asked.

"Too expensive," Kynes said. "Too much area to cover."

Paul leaned back in his corner. His truthsense, awareness of tone shadings, told him that Kynes was lying and telling half-truths. And he thought: If there's a relationship between spice and worms, killing the worms would destroy the spice.

"No one will have to walk out of the desert soon," the Duke said. "Trip these little transmitters at our necks and rescue is on its way. All our workers will be wearing them before long. We're setting up a special rescue service."

"Very commendable," Kynes said.

"Your tone says you don't agree," the Duke said.

"Agree? Of course I agree, but it won't be much use. Static electricity from sandstorms masks out many signals. Transmitters short out. They've been tried here before, you know. Arrakis is tough on equipment. And if a worm's hunting you there's not much time. Frequently, you have no more than fifteen or twenty minutes."

"What would you advise?" the Duke asked.

"You ask my advice?"

"As planetologist, yes."

"You'd follow my advice?"

"If I found it sensible."

"Very well, my Lord. Never travel alone."

The Duke turned his attention from the controls. "That's all?"

"That's all. Never travel alone."

"What if you're separated by a storm and forced down?" Halleck asked. "Isn't there anything you could do?"

"Any thing covers much territory," Kynes said.

"What would you do?" Paul asked.

Kynes turned a hard stare at the boy, brought his attention back to the Duke. "I'd remember to protect the integrity of my stillsuit. If I were outside the worm zone or in rock, I'd stay with the ship. If I were down in open sand, I'd get away from the ship as fast as I could. About a thousand meters would be far enough. Then I'd hide beneath my robe. A worm would get the ship, but it might miss me."

"Then what?" Halleck asked.

Kynes shrugged. "Wait for the worm to leave."

"That's all?" Paul asked.

"When the worm has gone, one may try to walk out," Kynes said. "You must walk softly, avoid drum sands, tidal dust basins--head for the nearest rock zone. There are many such zones. You might make it."

"Drum sand?" Halleck asked.

"A condition of sand compaction," Kynes said. "The slightest step sets it drumming. Worms always come to that."

"And a tidal dust basin?" the Duke asked.

"Certain depressions in the desert have filled with dust over the centuries.

Some are so vast they have currents and tides. All will swallow the unwary who step into them."

Halleck sat back, resumed strumming the baliset. Presently, he sang:

"Wild beasts of the desert do hunt there, Waiting for the innocents to pass.

Oh-h-h, tempt not the gods of the desert,

Lest you seek a lonely epitaph.

The perils of the--"

He broke off, leaned forward. "Dust cloud ahead, Sire."

"I see it, Gurney."

"That's what we seek," Kynes said.

Paul stretched up in the seat to peer ahead, saw a rolling yellow cloud low on the desert surface some thirty kilometers ahead.

"One of your factory crawlers," Kynes said. "It's on the surface and that means it's on spice. The cloud is vented sand being expelled after the spice has been centrifugally removed. There's no other cloud quite like it."

"Aircraft over it," the Duke said.

"I see two . . . three . . . four spotters," Kynes said. "They're watching for wormsign."

"Wormsign?" the Duke asked.