CHAPTER VII

"PERISCOPE AHOY!"


Sudden and unexpected was the knocking, and it found the boys unready to
answer it. They had no idea that the conspirators--either or both of
them--would come directly from their conference to the room where a
watch had been kept on them.

"Do you think he saw us?" asked Joe, in a whisper.

"S'posing he did?" demanded Charlie. "We have the goods on him, all
right."

Blake held up a hand to enjoin silence, though the remarks of his
friends had been made in the lowest of tones.

The knock was given again, and the voice of the Frenchman asked:

"Are you within, my friends of the camera? I wish to speak with you!"

"One moment!" called Blake, in a tone he tried to make pleasant. Then
he motioned to Joe and Charlie to seem to be busy over the midget
camera, which was kept ready for instant use. At the same moment Blake
threw a black focusing cloth over the mirror, for he thought the
Frenchman might notice that it was in a position to reflect whatever