Jack stepped to Lord Hastings’ side and shouted:

“Did we get ’em?”

Lord Hastings shook his head.

“I don’t know,” he replied. “We’ll go up again directly.”

He ordered the submarine to proceed ahead half a mile, and then rise.

This was done, and as the periscope once more took in the sight about, Lord Hastings, who gazed through it, stepped quickly aside and motioned to Jack to peer in. The lad did so, and stepped back with an exclamation of delight.

Frank also peered into the periscope, and uttered an exclamation of pleasure as his eyes took in the scene about.

Speeding forward in the wake of the German cruisers, which the periscope made plain, were all the German torpedo boats, except three. These lay helpless upon the surface of the sea, and it was plainly evident that they were settling rapidly.

Their crews were hurriedly getting out the small boats, and jumping overboard. The D-16 had done her work well.

Frank turned away from the periscope.

“Three notches in the table,” he said to Jack, who stood at his side.

“Right,” replied the latter briefly.

Feeling perfectly secure now, Lord Hastings ordered that the submarine be brought to the surface, and followed by Frank and Jack, he stepped out on the bridge.

They stepped out just in time to see the sinking of the Bluecher by the British cruiser Lion, and from their posts they watched the chase of the others. Frank and Jack were greatly surprised when the British admiral signalled for his ships to draw off.

“Great Scott!” exclaimed Frank. “He had them right in his hands. Why didn’t he follow ’em up?”

“It’s too deep for me,” said Jack, in some disgust.

“Come, come,” said Lord Hastings. “You must give the Admiral credit for having some sense, you know.”

“Then why did he do it?” questioned Frank.

“Why,” said Lord Hastings, “because, had he followed another mile, the entire British fleet might have been sent to the bottom.”

“What do you mean?” asked Jack.

“Mines,” replied Lord Hastings. “The enemy has reached the protection of his mine field.”

“I see,” said Frank, somewhat taken aback. “Of course. I should have known that the Admiral had some good reason for not following up his advantage.”

“You let your feelings get away with you sometimes,” said Lord Hastings.

“Well, I’ll promise not to do so any more,” said Frank.

“I wouldn’t make any rash promises, if I were you,” said Jack, with a smile.

“Well, I mean it,” said Frank.

“Oh, well, if you mean it, all right. Only you are liable to forget yourself if you are not careful.”

Jack turned to Lord Hastings.

“Which way now, sir?” he asked.

Lord Hastings was silent for some moments, but said finally:

“I guess we might as well cruise about here. Some of these other fellows are likely to come sneaking out, and we may nab them.”

“If you please, sir,” said Frank, “I believe I have a better plan than that.”

“Let’s have it,” said his commander briefly.

“Well,” said Frank, “these German submarines have been making raids on the coast of England. What’s the matter with our doing a little of that kind of work?”

“By Jove!” said Jack. “A good idea. What do you say, sir?” turning to Lord Hastings.

Lord Hastings was plainly undecided. It was evident that he looked with some favor upon the plan, but he hesitated, not because of fear, but rather because he was not entirely certain that it could be accomplished successfully.

“Where would you plan to make an attack?” he asked of Frank.

“Why, right in Heligoland, sir.”

“But the mines?”

Frank shrugged his shoulders.

“The Germans don’t pay much attention to our mines,” he said.

“Well, no, they don’t, that’s true,” agreed Lord Hastings.

“Besides,” said Jack, “we can go beneath the mines.”

“I guess we could do that,” agreed Lord Hastings. “While we cannot tell just where the mines lay, we have, nevertheless, a first-class map of Heligoland and the sea surrounding, and by paying careful attention we may be able to get through safely.”

“Then we shall make the attempt, sir?” asked Frank eagerly.

Lord Hastings smiled.

“Yes,” he said quietly.

“Good!” cried Jack and Frank in a single voice.

“It has always seemed strange to me,” said Frank, “why such an attempt has not been made before. The Germans do it. Why haven’t we?”

“Well,” said Lord Hastings, “I suppose the main reason is that Heligoland is too far away.”

“But the Germans have done it,” said Jack.

“True; but you must remember they have established a naval base at Ostend; and the distance from Ostend to Dover, and other British coast towns, is not as great as from the British coast to Heligoland.”

“I hadn’t thought of that,” said Frank. “However, I know this much. In every war in which the United States has engaged, some such desperate attempt has resulted successfully. Take Dewey at Manila, or Farragut at Mobile Bay. Both went right in, regardless of mines and forts.”

“That is true,” said Lord Hastings. “No one can dispute the bravery and daring of the American sailor. Nevertheless, it has always seemed to me to be foolhardy. Had it been absolutely necessary, it would have been different. But a blockade would have been just as effective.”

“I don’t know about that,” replied Frank. “Ever since the beginning of this war I have wondered why a British fleet didn’t try to get at the Germans.”

“Well, as nearly as I can make out,” said Lord Hastings, “it is because it has been believed unnecessary to take such a chance.”

“Of course,” said Frank, “we, in this submarine, will have a better chance of performing such a raid successfully than any other vessel, because we can go beneath the water, and stay there until we get ready to come up.”

“Right you are,” agreed Jack. “All we have to do is to figure the distance from here to a point where, being sure it is not mined, we wish to rise. Then, calculating our speed, we shall know just when to come up safely.”

“Perfectly simple,” said Lord Hastings with a smile, “if we don’t hit a mine before we get there.”

“Don’t you think, sir, that by going beneath the mines we will be successful?”

“If I didn’t I wouldn’t make the attempt,” said Lord Hastings dryly. “I remember how you did it when you sank that Turkish cruiser in the Dardanelles.”

“And had we had this vessel at our disposal,” said Jack, “we could have done considerable more damage. As it was we had to get back before we exhausted our air supply.”

“We have an advantage in that respect. There can be no question about that,” said Lord Hastings.

“Well, when shall we start, sir?” asked Frank.

“Immediately,” was the reply.

The three turned their eyes over the sea to where the British fleet, retiring, could be seen moving toward the west. One of the large cruisers, the Tiger, was being towed by a torpedo boat.

“Hope she is not badly damaged,” said Jack, noticing how the British cruiser staggered.

“She looks fit enough,” said Frank.

“The trouble is you can never tell by the looks,” said Lord Hastings. “However, I guess she is in no danger of sinking.”

“Let us hope her death list is small,” said Jack fervently.

“Let us hope so,” agreed Lord Hastings. “Come, we may as well go below.”

The commander of the D-16 descended from the bridge and the lads followed him.

“We may as well submerge here,” said Lord Hastings, “for every foot we advance on the surface of the water is putting us in the way of hitting a German mine. We can’t be too careful.”

“But it is hardly likely there would be any about here, sir,” said Frank.

“Have you forgotten what it was that caused Admiral Beatty to give up the pursuit of the enemy?” asked Lord Hastings.

“That’s so, sir,” said Frank. “I had forgotten.”

“Besides,” said Jack, “the Germans may have dropped more mines to cover their retreat.”

“Exactly,” said Lord Hastings.

“Well, let’s dive then,” said Frank.

“The sooner the better it will suit me,” said Jack.

“So be it then,” from Lord Hastings. “You may give the order, Mr. Templeton.”

Jack obeyed, and slowly, as the water was let into her tanks, the D-16 sank and sank, until, certain that she was beneath the enemy’s mines, Lord Hastings gave the command: “Full speed ahead!”