lay.

Only a few minutes were needed thus to follow the trail straight to the
clump of bushes on shore.

"Nobody leave the boat until we have a lantern ready," directed
Lieutenant Foster. "We don't want to tramp out the trail of the rascals
who laid that mine."

The marine lieutenant himself was the first to step ashore, and Jack
Benson was with him.

"Here are the footprints of the rascals," announced Foster, as the two
stepped cautiously into the bushes.

"Yes; there were just two of them here, apparently," replied Jack, after
studying the prints, and discovering the marks of only two different
sizes or kinds of shoes.

"Here's the imprint of a box," added Foster. "Good heavens, the
scoundrels had a regular magneto battery, insulated wire and all, for
firing that mine from the shore. Mr. Benson, they meant to blow your
boat into Kingdom Come!"

"It looks that way," replied Jack Benson, composedly.

On hearing that voice, so even and unaffected in its utterance,
Lieutenant Foster looked at the submarine boy keenly.

"By Jove, Benson, you're cool enough to be an admiral," muttered the