tilted mirrors--one in each stateroom--gave a perfect view of what went
on between the Frenchman and the German, as the boys preferred to think
Labenstein, but the watchers themselves were not observed. This they
could make sure of, for several times one or the other of the men across
the corridor looked up, and full into the mirror on their own wall, but
they gave no indication of observing anything out of the ordinary.

The mirrors were fastened in a tilted position to prevent them from
swinging as the ship rolled, and as they did not sway there was an
unchanged view to be had.

"I wonder what they're saying," observed Blake.

They could only guess, however, for though the men talked rapidly and
eagerly, as evidenced by their gestures, what they said was not audible.
Though both transoms were open, no sound came from the room opposite
where the boys were gathered. The men spoke too low for that.

"I guess they know it's dangerous to be found out," said Joe.

"But we ought to find out what it's about!" declared Macaroni.

"Yes, I think we ought," assented Blake. "This Frenchman has been in our
country, going about from camp to camp according to his own story, and
he must have picked up a lot of information."

"And he knows about our pictures, too!"

"Well, I don't imagine what we have taken, so far, will be of any great
value to Germany, assuming that Lieutenant Secor is a spy and has told