He was more inclined to believe, however, that the German spies, rendered furious by the escape of the coveted American seaplane had, as a last resort, started out to scour the water nearby in hopes of locating it.
"Frank!" whispered Billy again, "I think he glimpses the seaplane through the fog!"
The actions of the man holding the lantern indicated this, for he was plainly much excited, turning to his companion at the oars as though urging him to make more haste.
"Then it's high time we were off!" said Frank.
Again did Billy hold his breath as the possibility of the motors failing them in this great emergency flashed through his mind. But he need not have allowed himself this mental anxiety, for no such calamity befell them.
A shrill whistle was heard, evidently a signal to those in the second boat to inform them that the object of their search had been discovered. Then came the cheery whirr of the motors, accompanied by the churn of the busy propellers, and like a giant, double-winged dragonfly, the seaplane started along the surface of the water, followed by another burst of angry shouts.
"Duck! they may be going to shoot!" exclaimed Frank, suiting his actions to his own words.
That was just what did happen, for a volley of shots sounded, and had the motors not been making so much noise the boys might have heard the whistle of the passing leaden messengers.
There was no harm done, for, unable to longer see the speeding seaplane, those who used their weapons with such reckless abandon had to fire at random. Skimming the water like an aquatic bird, with a gradual but rapid increase to their speed, the seaplane soon began to rise.
Billy realized from that that Frank meant to make an ascension, possibly deeming it wise to get away from such a dangerous neighborhood as quickly as possible. And, as they anticipated, the reliable _Sea Eagle_ was doing her prettiest when called upon to show her fine points.
Once free from the sea, they rose until Frank felt sure of his position. He had switched on the electric searchlight, and the storage battery was of sufficient power to send the ray of white light far ahead. It could be turned to any quarter of the compass.
"Well, here we are off on our trial trip sooner than we expected," said Billy, meaning to draw the other out, for he was consumed by curiosity to know what was coming next.