"What is it?" he screamed in futile effort to lift his voice above the din.
But the Frenchman understood, and responded with a sweep of his arm toward the horizon ahead. And seeing nothing but cloud in the quarter indicated, Lanyard grasped the nature of a phenomenon which, from the first, had been vaguely troubling him. The reason why he had been able to perceive no real rim to the world was that the earth was all a-steam from the recent heavy rains; all the more remote distances were veiled with rising vapour. And now they were approaching the coast, to which, it seemed, the mists clung closest; for all the world before them slept beneath a blanket of dull grey.
Nor was it difficult now to understand why the aviator was ill at ease facing the prospect of navigating a Channel fog.
Several minutes later, he startled Lanyard with another peremptory touch on his arm followed by a significant glance over his shoulder.
Lanyard turned quickly.
Behind them, at a distance which he calculated roughly as two miles, the silhouette of a monoplane hung against the brilliant firmament, resembling, with its single spread of wings, more a solitary, soaring gull than any man-directed mechanism.
Only an infrequent and almost imperceptible shifting of the wings proved that it was moving.
He watched it for several seconds, in deepening perplexity and anxiety, finding it impossible to guess whether it were gaining or losing in that long chase, or who might be its pilot.
