“I see,” said Jack.  “Not a bad idea.”

“It was offered by the wireless operator,” continued Captain Griswold, “although he offered it unconsciously.”

“Explain,” Jack requested.

“Well, Harrington thought he heard his instrument clicking.  He figured it was you, whom we had just sighted.  He broke through the Germans on deck and dashed below.  He locked himself in his room and began talking to you.  Three of the enemy went after him and broke in the door, but I guess he had told you enough by that time.”

“I’d like a word with this Harrington,” said Jack.  “He is a brave man.  Where is he?”

“Dead,” said Captain Griswold quietly.

Jack jumped to his feet

“Dead?” he repeated.

“Yes.  After the Germans broke in the door, they overpowered him, tied him and then brought back on deck.  Said the German commander:  ’I’ll show you how we treat men who defy us.’  He stepped back several paces, drew his revolver and fired.  Then three of the enemy threw the body into the sea.  That’s when we jumped them, for it was more than we could stand.”

“Then who answered the wireless when I called a moment ago?”

“I did.”

“I guess that is enough, Captain,” said Jack.  He returned to the Essex.

CHAPTER XV

JACK GIVES CHASE

“Any sight of the submarine, Frank?” asked Jack, when he stepped on deck again.

“None,” was the reply.  “In accordance with instructions you gave before you went overside we dropped depth bombs in the spot where the U-Boat disappeared, but without result.”

“I guess he’s gone, then,” said Jack.  “But I’d like to get my hands on that fellow,” and he related to Frank the manner in which the German commander had shot down the wireless operator aboard the Ventura.

“By Jove!  What a murderous scoundrel!” muttered Frank.

Jack nodded.

“No worse than the rest of them, I’ll wager,” he said.  “But, hello!  The Ventura’s moving again.”

As soon as Jack had left the deck of the steamer, Captain Griswold had ordered the engines started and prepared for a quick dash to shore.

“There are likely to be more of those pesky submarines about here,” he muttered, “and the sooner I reach port the better.”

Accordingly he ordered full speed ahead.

“Do you know,” said Frank, “I’ve a hunch that the U-87 is not through with the Ventura.  You know how the German is.  He doesn’t like to admit he’s been licked, so I figure the submarine commander is likely to have gone ahead and will be awaiting the approach of the Ventura.”

“Now by George!  I wouldn’t be a bit surprised,” Jack agreed.  “Well, we’ll be ready for him.”

“What are you going to do, Jack?”

“I’ll show you.  Come.”

Jack dashed to the radio room, Frank at his heels.