Lord Hastings and Frank gazed in the direction indicated.  There a little object could be seen in the water.  It had the appearance of a small stick and beside it there appeared a black piece of cloth whipping in the breeze.

“Looks like the periscope of a submarine,” commented Frank.

“And it is,” declared Lord Hastings.  “Below quick!”

Jack sprang down the companionway, closely followed by Frank and Lord Hastings.  The conning tower closed behind them.

“Submerge to the tip of the periscope,” ordered Lord Hastings, and put his eye to the instrument as Jack repeated the command.

At that moment the other craft bobbed to the surface and Lord Hastings made out that the black cloth that fluttered in the breeze was nothing more nor less than a black flag.

“Pirates!” he muttered.  “What! at this age of the world?” and then a sudden thought flashed through his mind.

“I’ll wager a farm it’s Davis’ own crew,” he muttered.

“What’s that, sir?” asked Jack, who had caught his commander’s last words.

“Nothing much; only that Davis has found his own gang,” replied Lord Hastings quietly.  “Here, have a look.”

He stepped aside and Jack took his place at the periscope.  The lad uttered an exclamation of surprise.

“By Jove! he has, sir,” he ejaculated.  “I can see him swimming toward the submarine; and there is a man on the bridge waiting for him.  Can’t we launch a torpedo at her, sir?”

“I guess we can,” replied Lord Hastings.  “What do you make the range?”

“Hundred yards, sir,” replied Jack.  “Number three torpedo, sir!”

Lord Hastings touched a button and the signal board glowed.  But even as Jack would have given the command to fire, a new object suddenly rose to the surface of the water and he stayed his hand.

It was a third submarine, and Jack, instead of giving the command to fire, for which the men were eagerly waiting, cried: 

“Another submarine, sir!  Looks like a German.  She’s moving toward the pirate, sir!”

Lord Hastings stepped to the periscope, pushing Jack firmly aside.

“We’ll move off and let them fight it out,” he said.  “Full speed ahead, Mr. Templeton!”

CHAPTER XXVIII.

THE BATTLE AND THE ATTACK ON THE U-6.

Another few hundred yards from the two other submarines, Lord Hastings ordered the U-6 brought to a stop.

“We’ll stop here a bit and watch the battle,” he said.

The U-6 rose to the surface and the three officers ascended to the bridge.  The pirate craft, The Vulture, was still upon the surface and they were able to see that Davis at that moment had climbed over the side.  Together with the man who was already on the bridge he hurried below.

“Now they will submerge,” said Lord Hastings.

He was right, for a moment later The Vulture began to sink lower in the water.  At this moment the German craft fired her first torpedo.  It struck a hundred yards to the right of The Vulture.