ugging the walls of the low houses,
slip one by one into the wider shadow of the corner building. Still the
regular steps of the guard below told that the mysterious gathering had
not been discovered.

Presently four men emerged boldly from the shadow, and arm in arm, and
with unsteady gait approached the prison. In hiccoughing tones they sang
a Spanish drinking song. In the bright glare of the moonlight the boys
could see that they wore the uniform of Spain.

"Pshaw," said Harry, in a disgusted tone. "They are only a lot of
drunken Spanish soldiers after all, making their way back to the
barracks."

Harry was keenly disappointed. He had been confident that the strange
movements of the men indicated that some action was on foot which he
imagined Captain Dynamite was directing.

"But where are the others?" whispered Bert. "There are more in the
shadow."

"Probably waiting a chance to slip into the barracks without attracting
too much attention from their officers."

The four men reeled on. The regular pacing of the sentinel ceased and he
hailed the approaching quartet in a jocular way. They answered with
thick tongues and coarse laughter. Presently they passed out of view of
the boys, having come close within the shadow of the wall below them.

Then suddenly there was a muffled sound as of one trying to cry out with
a heavy pressure on his throat, the hard breathing of men desperately
struggling, and then silence.

The boys looked at one another in wonderment. What could it mean?
Possibly a drunken squabble between the men and the guard. Now the slow
pacing of the sentinel was resumed. Apparently the difficulty had been
adjusted.

"I think we might as well get to bed," said Harry, after they had waited
for ten minutes without any further developments. "There is nothing
doing to-night, I guess."

As he spoke, the cry of a night bird sounded on the still air, but,
strangely enough, it seemed to come from directly below their window,
instead of from the air above. Almost immediately an answering call was
heard in the distance, and then all was still again.

"I am not so sure, after all, that those men were Spaniards," said
Harry, as he turned eagerly to the window again.

"Why?"

"Did you hear those signals?"

"I heard a bird."

"I don't think it was a bird."

"Listen; if they were birds we shall hear them again."

The boys listened patiently for several minutes, but the sound was not
repeated.

"I