lights had almost wholly vanished by this time, showing the strict discipline that was in vogue in these stirring times. Frequently had daring German aviators appeared above Dunkirk to drop their bombs in the endeavor to damage the congested stores of the British troops, or strike a note of terror among the inhabitants of the Channel city.
Billy every little while twisted his head around and looked in different directions. But thick darkness lay about the floating seaplane, utterly concealing the shore as well as all vessels that lay further along in the harbor.
Possibly half an hour had passed in this way when Billy felt a sudden thrill. He started up, straining his hearing, as though to catch the repetition of some sound he believed he had heard.
Then, leaning over, he shook Frank.
“It’s Pudge signaling, Frank, or else I’m away off my base. Listen!” was what he told the other, in excited tones.
A minute later and they both caught the far-away sound of what seemed to be the winding blast of an Alpine hunter’s horn.
“Yes, it’s Pudge, all right, and he wants to hear from us if we’re within reach of the sound of his signal. Answer him, Billy!”
Already Billy had taken the horn from its fastenings, and no sooner had Frank given the order than he applied it to his lips. The sound that went forth, coming as it did from the blackness of the sea beyond, must have astonished any sailor on board the various steamers in the harbor.
Once, twice, three times did Billy give the peculiar note that Pudge knew so well. It must tell the absent chum that they were safe, and in the language of their secret code ask how things were going with him.
“There, he’s given us back the message word for word!” cried Billy, as they caught the faint but positive reply from the unseen shore, perhaps at the deserted hangar. “Frank, he’s all right! That takes a big load off our minds.”
“Yes, now I can rest easy!” declared the other. “As that star isn’t close to the sea as yet, Billy, if you don’t mind, I think I’ll try for a few more winks of sleep. Pudge will go back to town and stay at our lodgings until we turn up, or send him a message. Everything is working finely.”
“For us,” added Billy, chuckling. “But think how mad those spies must be over losing the prize they thought was sure to fall into their hands. Why, I wouldn’t be surprised if they discounted the capture of our seaplane, and over in Belgium were ready to start to work making copies of the same as soon as the sample could be delivered.”
Billy appeared to be highly amused, for he chuckled to himself for several minutes while picturing the disappointment of the baffled plotters. Then once more he settled down to his task of serving as “officer of the watch.”
As the minutes crept on, Billy began to observe the gradual approach of the star to the vague region where sea and heavens merged in one. In fact, Billy was yawning quite frequently now. He found himself fairly comfortable, thanks to the warmth of that leather fleece-lined jacket, and the hood which he had drawn partly over his head. Still, it was not very delightful, sitting there on the water; and perhaps the boy’s thoughts frequently turned toward the bed he was missing.
“I wonder which way we’re drifting now?” he suddenly asked himself; he immediately set to work trying to answer his question by observing the direction of the tide, as well as by the light current of air.
When next he thought to turn his head so as to glance backward, Billy received a bit of a shock. A sort of thin haze had settled down on the water by now, but through this he had discovered two moving lights. They looked very queer as seen in that foggy atmosphere; but Billy was smart enough to know what they stood for.
He immediately awoke Frank, whispering the astonishing news in his ear.
CHAPTER V.
A NIGHT ON THE CHANNEL
“They’re looking for us, and they’ve got lanterns, Frank!” was what the one on guard said in a low tone as he pulled his chum’s sleeve.
Frank was wide-awake instantly, and one quick glance showed him the approaching peril.
“Yes, you’re right about it, Billy,” he observed cautiously, and if there was a little quiver to his voice that was no more than might be expected under the exciting conditions by which they were surrounded.
“How queer the lights look swinging along close to the water, and in that fog, too. They are heading out this way, I’m afraid, Frank.”
“It seems so, Billy.”
“Hadn’t we better get under way, then?” continued the nervous one.
“No hurry,” Frank told him. “They may happen to swing around one way or the other and miss us. We’ll wait and find out. You know we can get moving with a second’s warning. Now let’s watch and see what happens.”
Billy could be heard sighing every now and then. Doubtless, as he sat there with his head turned halfway around, observing the creeping movements of those two strange lights through the fog that hugged the surface of the water, he was thinking it the most exciting moment of his whole career.
Then a new idea seemed to have lodged in his brain, for again he whispered to his companion.
“There may be more than those two boats, Frank!”
“Possible but not probable,” Frank replied.
“What if, when we started off with a rush, one happened to get in the way?” pursued Billy.
“I’d be sorry for the men in that boat, that’s all, Billy!” was the laconic reply he received, and apparently it satisfied the other, for he did not pursue the subject any further.
Meanwhile it became apparent that the searching boats were gradually drawing nearer the floating seaplane. Unless they changed their course very soon those in the hostile craft would be likely to make a discovery that must fill them with delight.
“Are we headed right for a start, Frank?” asked Billy, a minute later.
Frank himself had been considering that very thing. The influence of the tide seemed to have swung the seaplane around a little more than he liked; but then this could be easily remedied, for they were prepared for such a possibility when on the water.
There was a little paddle within reach of Frank’s hand; all he had to do was to pull a couple of cords, and it was in his possession.
Softly he worked it through the water. Frank had spent many happy hours in a canoe when on his outing trips, and knew how to wield a paddle like an expert. He had even taken lessons from one of those old-time guides accustomed, in years gone by, to using a birch bark canoe in stealing up on deer when jacklight hunting was not banned by the law.
Consequently he now used his paddle without making the slightest noise; and under its magic influence the clumsy craft gradually veered until he had its spoon-shaped bow heading just where he wanted it. Then he handed the paddle to Billy to replace as best he might.
They could by this time vaguely make out the nearer boat, and also the indistinct figures of two men. One of these was rowing, while the other held up the lantern.
Of course, there was nothing to tell Frank who they might be. Perhaps, in these stirring times, the waters of the harbor had to be patrolled by guards on the watch for submarines or other perils. These protectors of shipping may have heard or seen enough that was suspicious to warrant a search of the adjacent waters.
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