Through the Gulf of Finland into the Baltic the D-16 made her way rapidly, remaining upon the surface of the water, for in these seas there was no danger of encountering an enemy. Some miles from the mouth of the Kiel canal, however, Lord Hastings gave the command to submerge, and the little submarine, sinking gently, hurried on, at a somewhat reduced speed, but making good time nevertheless.

On this second passage of the canal, Lord Hastings decided to make no raid upon the enemy’s fleet cooped up within it, and accordingly the D-16, running close to the bottom, guided by Lord Hastings’ own hand, made the trip in safety, without encountering a single one of the enemy’s under-the-sea fighters. However, she did not rise immediately when she was once more in the North Sea, for these waters were mined for miles, and it was necessary for the D-16 to pass under the mined area before coming again to the surface.

But, going more swiftly now, the British submarine soon reached a zone of comparative safety and Lord Hastings gave the command to come to the surface once more. Then, followed by Frank and Jack, he stepped on to the bridge for a breath of the cool air.

“Well, I was sure we would get through safely, and we have,” said Jack, as he peered off across the water.

“And we have accomplished,” said Lord Hastings, “such a feat as was never before attempted, and one that has been rated as impossible. You lads are both deserving of the greatest praise for your coolness and bravery.”

“No more than our commander, I am sure,” replied Frank quietly. “Had it not been for you, the trip never could have been made.”

“But,” said his commander, “had it not been for you lads, the trip would never have been thought of.”

“Well,” said Frank with a laugh, “we’ll call it square all around and let it go at that.”

“Suits me,” declared Lord Hastings, also laughing.

“It seems to me,” said Jack, “that the crew is just as deserving of praise.”

“So they are,” said Lord Hastings, “and I shall see that their names are given special mention in my report to the Admiralty.”

“Which reminds me,” said Frank, “that we still have the German prisoner aboard.”

“By Jove!” exclaimed Lord Hastings. “Do you know I had forgotten all about him?”

“What do you intend to do with him?” asked Frank.

“Well,” said Lord Hastings slowly, “I had intended giving him his liberty at the first opportunity. So far none has presented itself. If something doesn’t turn up soon, I fear I shall have to turn him over to the Dover military authorities as a prisoner of war.”

Jack gave vent to an expressive whistle.

“After what you have told him,” he said, “that will make it rather hard.”

“So it will,” admitted his commander, “but if half a chance turns up I shall see that he is set free. For had it not been for him, Frank, you would probably be imprisoned in Berlin right now.”

“That is undoubtedly true,” said Frank, “and I am properly grateful.”

“We’ll see,” said Lord Hastings, and this put an end, for the time being, to the subject.

Still running at full speed upon the surface, the D-16 was making rapid headway toward the British coast.

“We had best be careful, sir,” said Jack. “Remember what the prisoner told us about the submarine blockade.”

“Right,” was the reply. “Of course there is a safety zone for the protection of neutral ships, but as we do not know just where these fellows are likely to be hanging about, we had better take a stitch in time and go down a ways.”

He turned to give the command, but before the words could leave his lips, he turned suddenly again at a cry from Frank.

“What’s up now?” he demanded.

For answer Frank pointed straight ahead toward the distant horizon.

“Looks like a ship in some kind of trouble, sir.”

Lord Hastings raised his glass to his eyes and peered through it long and intently.

“She’s in distress, that’s sure,” he said, lowering the glass at last. “But I can’t make her out from this distance. She doesn’t look like a ship of war, though.”

“Probably some merchantman victim of the German submarine blockade,” said Jack.

“That’s about the size of it,” Frank agreed.

“Well,” said Lord Hastings, “we’ll go closer and see, although there is nothing we can do for them.”

The object of this conversation lay almost due west, a trifle north. The head of the D-16 was consequently turned slightly, and she made for the vessel at top speed. The three officers remained upon the bridge, barely rising above the water, and at last they were able to make out the ship.

“Merchantman, all right!” said Jack.

“Yes!” exclaimed Frank, becoming suddenly excited, “and do you make out her colors?”

Jack took another look.

“By Jove!” he exclaimed.

Lord Hastings also raised his glass to his eyes again, then started back with an exclamation of surprise.

“They have gone too far this time,” he said slowly. “This means trouble.”

For the colors flying at the masthead of the sinking merchant ship were the Stars and Stripes!

“The United States will not let them get away with anything like that,” declared Frank vehemently.

“Don’t be too sure,” replied Lord Hastings. “Remember the incident of the firing of Turkish forts upon an American battleship launch at Beirut. Nothing came of that.”

“But,” protested Frank, “it is inconceivable that the United States will not take action if a German submarine has sent one of her merchant ships to the bottom.”

“Looks like an act of war to me,” said Jack.

“Germany will probably claim,” said Lord Hastings, “that the ship did not stay within the established safety channel, or else deny that a German submarine is responsible.”

“She might do the latter,” said Frank, “but I don’t believe the United States would accept the former explanation.”

But the United States eventually did, as it developed later, although she lodged a formal protest through her ambassador at Berlin.

“B-o-s-n-i-a,” Frank spelled out the name of the sinking ship, as the D-16 drew closer.

“I wonder if her crew is safe?” he asked anxiously.

Lord Hastings pointed across the water.

“You can see some of them in the small boats,” he said. “I hope they all get away. The submarine must have torpedoed them without warning.”

“I haven’t any doubt of that,” said Frank, “although it is against all rules of civilized warfare.”

“I do not claim that the Germans are conducting a civilized war,” said Lord Hastings quietly. “The tales of cruelties coming out of Belgium augur decidedly against that.”

At this juncture a fourth figure ascended to the bridge. It was that of the German prisoner.

He took in the situation at a glance, and turned to Lord Hastings with a faint smile.

“A victim of the blockade, I suppose?” he questioned.

Lord Hastings nodded.

“Looks like it,” he said briefly, “and an American ship at that.”

The German muttered an imprecation under his breath.

“I was afraid something like that would happen,” he said. “I never was in favor with the policy of torpedoing neutral ships, whether in the blockaded zone or not. To my way of thinking, no good can come of it.”

“I have an idea that no good for Germany will come from this,” said Lord Hastings.

“Still,” said the prisoner hopefully, “it may be all right. The United States will endeavor to stay out of the war on any pretext. Besides, she is woefully slow to act, as has been proved by her actions toward Mexico. Therefore this may be overlooked.”

“Don’t you believe it,” cried Frank hotly. “The United States will protect her citizens and property the world over.”

“Well,” said the German with a scornful smile, “it’s about time she began to do it.”

“What do you mean?” asked Frank taking a step toward the prisoner. “Do you mean we are all cowards?”

“Well, hardly that,” replied the German, with a faint smile, “but——”

“But nothing,” cried Frank. “We don’t raise such things as cowards in the United States.”

The German lifted his eyebrows skeptically, and Frank grew angrier.

“You’ll try us too far some of these days,” he said, “and we’ll do you like Dewey did some of your ships at Manila. He said: ‘Get out of my way and don’t interfere with me or I shall send you all to the bottom.’”

The German’s face flushed. Plainly he also was growing angry.

“If you try it,” he said, “you’ll wish you hadn’t.”

“Why?” demanded Frank. “Do you think you can lick us?”

“I don’t think there is any question about it!” was the reply.

“Well, don’t you ever fool yourselves!” exclaimed Frank angrily. “We——”

“Here, here,” exclaimed Lord Hastings at this juncture, laying a hand upon Frank’s arm. “No more of this. Remember, Frank, that this man is a prisoner and should be treated courteously.”

Frank drew away grumbling.

“Then he wants to let my country alone,” he protested.

The German, also, would have continued the argument, but Lord Hastings settled the matter.

“Not another word of this,” he said sternly, and Frank and the prisoner bowed to this command.

“There she goes,” cried Lord Hastings suddenly, pointing to the sinking ship.

All gazed toward the vessel. Slowly she rose high in the air, seemed to hang in the very air for a few brief moments, then dived and the waters closed over her. The American Steamship Bosnia, torpedoed by a German submarine or shattered by a German mine, sank to the bottom of the North Sea.