Temporarily Vauquelin returned entire attention to the management of the biplane. The wind was now blowing more fitfully, creating pockets—those holes in the air so dreaded by cloud pilots—and in quest of more constant resistance the aviator was swinging his craft in a wide northerly curve, climbing ever higher and more high.
The earth soon lost all semblance of design; even the twisted silver wire of the Seine vanished, far over to the left; remained only the effect of firm suspension in that high blue vault, of a continuous low of iced water in the face, together with the tuneless chanting of the motor.
After some forty minutes of this—it may have been an hour, for time was then an incalculable thing—Lanyard, in a mood of abnormal sensitiveness, began to divine additional disquiet in the mind of the aviator, and stared until he caught his eye.
"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.