man rose together.

Whew! What a powerful breath the man took! Then he steered the cylinder
carefully against the hull, and managed to hold it there until he could
reach a piece of cordage and make the cylinder fast.

This done, he dashed below, thumping hard on the door of the stateroom
occupied by Captain Jack Benson and Hal Hastings.

"Eh? What is it?" called Jack, almost instantly.

"You're wanted on deck, Captain--instantly," replied the dripping
machinist.

"Oh, all right, Williamson," and Benson's feet hit the stateroom floor.

A minute later he was above, Hal following only some twenty seconds
behind his young chief.

Williamson swiftly told how he had heard the bumping against the hull,
and how he had found the cylinder, with a wire connection.

"Gunboat, ahoy!" roared Captain Jack, snatching up a megaphone and
holding it to his lips.

The response was prompt. In less than three minutes a cutter, containing
an officer, a corporal and four marines, was alongside.

"The first thing for us to do is to take that cylinder aboard the
'Waverly' and investigate it," decided Ensign Foss. "I'll leave the