“Now the pump,” said the captain, “you will find a place for it on the other side of the tank.”

This was adjusted to the captain’s satisfaction.

“Now,” said the captain, “all you have to do is to stick this nozzle down the conning tower, turn it so as to give the gas full play and pump.  Of course the gas would carry without the pump, but you save time this way.”

“One moment, Captain,” said Jack.  “How about ourselves?  Won’t the gas affect us as well as the Germans?”

Captain Griswold clapped a hand to his side.

“Now what do you think of that?” he demanded.  “I must be getting old before my time.  Here, Lands,” he called one of his own men, who approached.  “Go and tell Helgoson I want two dozen of those gas masks in the store room; and hustle.”

The sailor hurried away.  He was back within fifteen minutes, and Captain Griswold distributed the gas masks.  Then he took the nozzle of the hose, poked it down the conning tower and looked around.

“Everybody ready?” he asked.

Jack also glanced around.  Every man on the deck of the submarine wore a gas mask.

“All right, sir,” said Jack.

“Then you turn that screw there when I give the word.  All right?  Then shoot!”

There was a hissing sound as Jack turned on the gas.

For perhaps ten minutes Captain Griswold moved the hose to and fro.  Then he pulled it forth and motioned Jack to turn the screw again.  This the lad did.  Captain Griswold then motioned the others to follow him, and led the way below.

At the foot of the conning tower they stumbled across several figures, overcome by the fumes.  These were quickly bound and passed up on deck to the men who remained behind.

The search of the submarine took perhaps half an hour.  Every nook and cranny was explored.  The gas had done its work well.  Apparently it had poured in so rapidly that the crew had had no time to open the portholes, for they were all closed.  Captain Griswold opened them now.

Then he led the way on deck, and closing the conning tower, removed his gas mask.  The others followed his example.

“Simple, wasn’t it?” said the captain of the Ventura to Jack, grinning like a boy.  “Lucky I happened to come back.”

“It is indeed,” said Jack.  “But won’t this gas affect us, Captain?”

“Not out here,” was the reply.  “It’s not strong enough.  You can barely smell it now.  Now what are you going to do with the submarine?”

Jack considered a moment.

“I’ll tell you Captain,” he said, “it strikes me that this submarine is really the prize of the Ventura.  At all events, I cannot be bothered with it, for there is still patrol work to do in these waters.  Can’t you tow her into port?”

“Can’t I?” shouted Captain Griswold.  “You bet I can.  You give the word and I’ll tie her on behind right now.”

“All right, Captain,” said Jack.  “She’s yours.”