se watch has been kept!"

"We haven't seen him at all!" stated Ned, just as firmly.

"We shall have to search the vessel!" affirmed the orderly. "You will
please remain aboard for a short time."

Quickly ascending the ladder the man summoned another soldier from the
shore. Together the two made a hasty examination of the boat.

Unable to discover any trace of the missing prisoner they shook their
heads as if greatly puzzled. Now and again they glanced at the boys,
exchanging at the same time comments in German.

"Come with us," finally said the first visitor.

Obediently the lads followed ashore. They were conducted to the office
building, where they were shown into the presence of General Gruenwold at
once. In a few words the orderly stated the case.

"This looks serious, boys," commented the General. "Can you not explain
the whereabouts of Mackinder? He is a prisoner, you know!"

"We know nothing of the man!" declared Ned, earnestly. "We don't like him
and surely would not think of assisting him to escape!"

"If you please, sir," began the orderly, "it is the opinion of my comrade
and myself that the boys have done away with Mackinder!"

"What!" almost shouted Gruenwold, rising from his chair.

"Yes, sir," continued the man. "There was found in the boat much blood. A
hammer in their tool kit was also blood-stained. We think they possibly
made away with him and might have dropped his body into the harbor very
quietly without being seen from shore!"

"This is serious, indeed!" gasped Gruenwold. "We shall investigate this
in the morning. Meanwhile, search the vessel again. The boys will be put
in the guardhouse until tomorrow."

Protests on the part of the lads were unavailing. Gruenwold was
determined in his decision. Ned's explanation of the presence of the
blood in the vessel was listened to, but without influencing the general.

Directly the lads found themselves in a room used for the accommodation
of such prisoners as might need confinement for a time. The island
boasted no regular prison, but a house not far from the water had been
utilized for the purpose. A guard paced a beat in the vicinity.

Disappointed and angry at the turn of affairs the lads made but a poor
supper of the food that was brought to them. Presently they composed
themselves to sleep on the floor.

A tapping at the window attracted their attention.

CHAPTER XIV

HELPED BY AN ENEMY

"What's that?" inquired Ned, start