marine officer, admiringly.

"Why, this doesn't seem to be a joke on me," replied Captain, Jack,
smiling back at the lieutenant.

"A joke!"

"It's one on the Secret Service," laughed Jack, quietly. "They are the
ones who are supposed to have the job of keeping off spies and all of
their kind."

"Yes; this certainly came from the spies, or their friends," muttered
Lieutenant Foster. "Jove, but we have a desperate crowd to deal with
when they'll go to such a length as this in time of peace!"

"Oh, it may all turn out to be a joke," put Hal, quietly. "Some one
may have been doing this to try us out. That metal cylinder may prove
to have been loaded with ginger-bread or peanuts. If anyone has been
trying a joke on us, then I'm mighty glad we didn't get rattled."

"I reckon we shall soon know just what that cylinder did contain,"
muttered Lieutenant Foster. "Here's another cutter coming from the
'Waverly,' and I think I make out Lieutenant Commander Kimball in the
stern-sheets."

It was, indeed, the lieutenant commander. As he stepped ashore, his
face coming into the circle of light cast by the lantern, his features
were seen to be white with anxiety.

"We have just looked into the cylinder," he announced, in a low voice.