By this time the boys had learned to pitch and strike camp in the briefest possible time—in short, to take very good care of themselves under most of the varying conditions which such a life as they were leading entailed.
They had made camp this night on a rooky promontory, under clear skies and with bright promise for the morrow.
Tad gave a quick start as a flash of lightning disclosed something moving on the far side of the camp.
"What's that!" he breathed.
With quick intuition, the boy stepped back behind the flap of the tent, and, peering out, waited for the next flash with eyes fixed upon the spot where he thought he had observed something that did not belong there.
"Humph! I must be imagining things tonight," he muttered, when, after three or four illuminations, he had discovered nothing further.
Tad was about to return to his cot when his attention was once more attracted to the spot. And what he saw this time thrilled him through and through.
A man was cautiously leading two of the ponies from camp, just back of
Professor Zepplin's tent.
The boy paused with one hand raised above his head, prepared to pull the tent flap quickly back in place in case the stranger chanced to glance that way, all the while gazing at the man with unbelieving eyes.
Was he dreaming? Tad wondered, pinching himself to make sure that he really was awake.