There was nothing for Jack to do but obey or be shot. His hands went high in the air, but he still retained the valuable papers.
"Drop those papers," was the next command.
Jack obeyed and the papers fluttered to his feet. The German reached out and picked them up with his left hand while with his right he still covered the lad with his revolver.
"So you're a spy, eh?" said the German.
Jack made no reply, but a gleam of hope lighted up his eye; for, Frank, chancing to turn for some unexplainable reason, had taken in the situation and was now advancing on tiptoe to his friend's aid.
"How did you get here?" demanded the German, making ready to rise.
Again Jack made no reply; but none was necessary, for at that moment Frank had come within striking distance. His arm rose and fell, and as his revolver butt descended upon the German's head, the latter toppled over in a heap.
Quickly, Jack stooped and again recovered the papers he had taken so much pains to get.
"Come on!" cried Frank. "We haven't time to fool around here. The rest of this crowd is likely to wake up in a minute or two."
Jack followed his friend across the sand. They laid hold of the hydroplane and rolled it toward the water. In it went with a splash and Frank cried: