“Are there any big eagles around here?” asked Jack, quickly turning to Long Gun.

But the Indian did not seem to hear. He was staring up into the black sky.

The noise passed on, the throbbing becoming fainter.

Then Long Gun cried out:

“Great spirit! Danger come! Bad luck!”

With a howl that did more to frighten the boys than had the mysterious sound, the Indian made a dive for the tent, and hid himself under his blankets.


CHAPTER XXI
THE DEADLY GAS