ld see its one light, for
economy in the use of all means for illumination was a cardinal feature
of the German military orders in those days of scarcity.

The car stopped in front of the house, and a man jumped out. Tom saw
that he wore a uniform of some sort, and judged that he might be a
captain, at least. There was a second figure on the front seat, also in
the dark-green garb of a soldier, but a private possibly.

The two young Americans crouched amidst the dense bushes and listened.
So many thrilling things were happening in rapid succession that their
pulses beat with unwonted speed.

Before this the sound of the approaching car must have reached the ears
of the man they had seen pacing the floor in the spacious room that
looked like a library. There were many books in cases and on shelves,
while pictures and boars' heads decorated the walls.

Potzfeldt opened the door just as the officer alighted, and there was an
exchange of stiff military salutations. Tom discovered that his guess
was a true one, for the man of the house addressed the other as
"Captain."

It was too bad that they spoke in German as they stood by the open door.
Jack for once bitterly regretted the fact that he had never taken up the
study of that language when at school, as he might have done easily
enough. It would have paid him handsomely just then, he believed.

The two men talked rapidly. Apparently the officer was asking questions,
and demanding something, for in another minute Carl Potzfeldt took an
object out of a bill book and handed it to the other. As near as the
watchers could make out this object was a slip of paper, very small, but
handled as though it might be exceedingly precious.

Jack had a sudden recollection of a correspondingly minute slip of paper
which he and Tom had found hidden in that little receptacle attached to
the leg of the homing pigeon the latter had shot.

More talk followed between the two men. Presently the man turned and
hastened inside again. He had left the door standing open, however, with
the German officer waiting as if for something he had come after besides
the scrap of paper.

Jack knew now that the man in uniform was from the headquarters of the
Crown Prince. That accounted for the numerous marks of car tires which
Tom had discovered on the drive. This lonely house by the roadside on
the way to Metz was a nest of spies. Perhaps Carl Potzfeldt might be the
chief, through whom negotiations we