Edwards, also about to leap overboard at that moment, paused, raised his revolver, took careful aim at Davis and fired.  Davis uttered a hoarse cry, dropped his own weapon, and crumpled up on the deck.  Edwards smiled grimly, dropped his revolver and leaped lightly into the water.

He came up a moment later beside Jack, who was treading water while he awaited him.

“Which way, sir?” asked Edwards.  “You know where we are.  I don’t.”

“This,” said Jack, “is the Thames.  We’ll have no trouble making shore.  Follow me.”

Edwards did so and a few moments later both stood dripping on land.

“Now where to, sir?” asked Edwards.

“We’ll have to hunt up Lord Hastings.  He’s gone to make his report to the British authorities.  By inquiring a bit we should have no trouble finding him.”

The lad was right.  A subordinate officer directed them to the quarters of General Hamilton, where Jack felt sure he would find his commander.  At the door of the general’s quarters an orderly halted them.

“Is Lord Hastings here?” demanded Jack.

“He is closeted with the general,” was the reply.

“Well,” said Jack, “you tell him his first officer is here and wants to see him immediately.”

The orderly hesitated, but a second look at Jack and he did as commanded.  A moment later Lord Hastings dashed out, closely followed by Frank.

“What’s wrong?” he demanded.

“Nothing, only that we have been chased off the submarine,” replied Jack quietly.  “Davis headed a conspiracy to capture the vessel and I was unable to act quickly enough.  Edwards and I escaped.”

“And O’Brien and McDonald?” inquired Lord Hastings.

“Dead!”

“How about Davis and the others?  Weren’t you able to account for any of them?”

“A few, sir,” returned Jack briefly, “but Davis——­”

“I think I got Davis, sir,” Edwards interrupted quietly.  “I took a shot at him just before I went over the side.  He went down.”

“I’m glad to hear that,” returned Lord Hastings.  “He is too dangerous a man to be at large.  Besides, without him, the Germans will hardly get very far.”

He turned to General Hamilton, who had followed him from his room, and added:  “If you’ll be so kind as to give me a detail of ten men, sir, I’ll go and see about this matter.  It may be that we can recapture the vessel.”

General Hamilton acted quickly.  He summoned an orderly and commanded that ten men be placed at Lord Hastings’ disposal immediately.  The men appeared on the run a moment later and Lord Hastings led them toward the river, where they all embarked in a small motorboat and headed for the spot where they had left the submarine.

But there was no submarine to be found.  It had disappeared.

Lord Hastings uttered an exclamation of chagrin.

“They’ve gone,” he said.  “Edwards, I guess you didn’t hurt Davis very bad.  I don’t suppose there was a sailor aboard who could navigate the vessel.  Davis probably could.”