is to keep it down to human body heat. Normally it is very much higher than yours. And when, due to exercise and metabolic speed-up, excess energy is accumulated, it is satisfying to us to radiate it. You get the same release by deep sighs, by long breaths, by stretching your limbs. Unfortunately, when we radiate rapidly in air, we glow. It has made us conspicuous."

"We all have our hobbies," said Evers, shifting his swollen ankle and wincing. "Did you ever hear of the Liars' Club? If you like to hold office, you could be President."

Dzell did not appear offended. "I said you would not believe. When it is again my turn to explore, I will search for your Liars' Club. I can see from your thoughts that it is concerned with jokes. And this is the one thing about you that we have not mastered. Other explorers have also felt baffled. The function of odd misstatement escapes us."

"'Other explorers'?" Evers' voice lost its note of ridicule, and Drinkard leaned forward with new interest. "You mean there are a lot of incandescent guys like you prowling about?"

Dzell shrugged. "All are not from my environment. Many are so unlike you that they cannot mingle and so must observe from hiding. Others cannot exist in your atmosphere without artificial help. We contact them constantly. Your unawareness is a marvel to us all. For creatures so well supplied with adaptations for sensation, you are indeed blind."

Chuck Evers drew a long breath. "If I could radiate, I'd be lit up like a theater marquee. You sound like an old professor I had once. I didn't understand him, either."

Had Dzell comprehended humor, he would have smiled. But he simply turned away with finality.

"Dzorr is waiting by the glacier," he said. "We have plans for this time. When you return to the settlements below, it would perhaps be wisest not to attempt to explain the lights."

The next instant, he was gone without a sound.

The two young men sat silently by the dying fire. A few minutes later, both looked up, as though by signal, toward the upper reaches of the glacier. Two glowing spots, dull cherry red, moved steadily across the ice. They were visible for brief minutes, then slowly faded.

Chuck Evers shifted restlessly. He shook his head as though a bee were buzzing inside it.

"Did you hear something?" he asked.

"Not with my ears," said Drinkard. "But as plain as a voice, Dzell just said to my brain 'Good luck, boys!' in good American."

"Now I know I'm nuts," grunted Chuck Evers. "That's what he said to me."

To descend Precipice Peak, even if only from Bighorn Glacier, is no fit task for a cripple. Still, Evers and Drinkard knew it had to be done, so, in the early morning, they set about it without haste and without complaint.

Where the going allowed it, big John simply back-packed Evers. They made use of every ledge, for Chuck could rappel himself down spots he could not climb or be carried. Both were mountain men and tough, but by mid-afternoon they knew they had had enough.

So nothing had ever looked better than the cheerful figure of Heine Kolb, slouched in the saddle of his dainty-footed pinto mare, and leading two pack horses loaded with fish panniers. The ranger was headed down.

"The complete Samaritan, that's me," said Heine. "I haul fish up and Poor Fish down. Two loads for the price of one."

"We will accept your insults along with the ride," Chuck Evers said wearily. "I never knew what a pretty thing a horse could be!"

Heine dropped his fish cans, helped to hoist Evers onto one of the pack horses. Drinkard climbed aboard the other.

"What happened?" asked the ranger. "I saw by the headquarters record that you were going up."

Evers shrugged and John Drinkard said, "The boy here was playing rockchuck on the stretch below the glacier and one rolled with him." Evers grinned wryly, and John added, "It could happen to anybody, but it's the kind of thing that's partial to tender-feet."

"Next time,"