Roque had evidently cleared up a disturbing point in his mind as he muttered something about a "fool story," and "I might have known there was nothing to it."
Having satisfied himself that it was still an independent little war at this remote point from the main field of operations, and that he had been misled by some advices previously received, the chief observer passed the word to his pilot to back-track, at the same time giving signal to the companion biplane.
As the machines swung around for the return flight, and drew closer together, Renos gave a megaphone yell through a hollow formed by his hands:
"Speed for your lives, they're on the wing!"
Above the gentle slopes on the west, leading to the summit of the mountain ranges, aircraft had arisen, looking, at a distance, like black dragonflies.
At the same moment, the invading biplanes also had a reminder to hurry from the fortress they were leaving behind.
A shell burst seemingly quite close to the machine Henri was driving, and the craft dipped far to one side.
Billy's heart beat up to his throat when he saw the break in the flight.
But his was an exulting cry when the momentarily stricken flyer righted, and bored ahead.