. "Nearly
suffocated, too. He couldn't have lasted there much longer. His heart
action is pretty weak even yet. Better have him removed to his bed, and
kept there for the rest of the day, at least."

At that moment Jerry came hurrying down the deck. He was visibly
excited, but, unlike Slim, he did not forget that not only must a
soldier never permit his feelings to run away with him, but that he must
be equally mindful of respect for superiors.

And so, even as two men carried Lieutenant Mackinson away, he remained
standing at salute, waiting for the captain to recognize him with a
return of the salute.

"And now what?" asked the captain.

Jerry stepped forward, with difficulty repressing his excitement.

"I stepped out of the wireless room for only a few moments," he said.
"When I returned I found this lying upon the table."

He opened his left hand. In it lay a piece of light chain, both ends
broken.

"Beside it," he continued, "was this note."

From his pocket he extracted a piece of paper, the edges of which were
roughly torn. He handed it to the captain, who read aloud:

"Let this be a warning that no further interference will be of
avail."

The captain looked from the note to the chain. There was no further word
on the paper, and no signature.

"I believe, sir," said Jerry, "that this is the rest of the chain which
was attached to the iron cross torn from the man caught in the battery
room."

The senior officer of the vessel took from his pocket the cross, with
its two bits of chain still dangling from it. He placed the ends to the
chain which Jerry had found in the wireless room.

"You are right," he said simply. And there could be no doubt about it.

The captain's face clearly showed the worry on his mind. The ship's
physician, who had been told all about the affair, immediately after
Joe's discovery of, and battle with, the mysterious stranger, appeared
equally anxious.

"A man is discovered at night in the battery room of the wireless
department of this ship, clearly upon an unfriendly mission," said the
captain, half to himself and half for the benefit of the others, summing
up the evidence thus far known to them. "He gives battle to the man who
discovers him, and finally succeeds in knocking that man out and
escaping. But he leaves behind him a portable wireless instrument, and
a German iron cross, with two bits of the chain attached.

"A few hours later that same night he retu