"I see a light about a point off the port bow!"

"What do you make it out to be?"

"I think it is a lighthouse!" declared Jimmie.

"Margate!" murmured Mackinder. "We are safe enough now, but be careful about the money, boys!"

"Sail ho!" rang out Jimmie's voice again.

CHAPTER XXII

MORE MYSTERY

"What do you see now, Jimmie?" asked Ned anxiously, stepping to the foot of the ladder.

"There's a small steamer coming up rapidly from the starboard side,"

replied the lookout.

"Perhaps we'd better dive again," suggested Ned.

"Aw, go on!" protested Jimmie. "What's the use of diving every time anything comes along? We're neutral!"

"We are, yes," agreed Ned, "but this 'U-13' name is not neutral, and if the steamer is an English vessel they'll probably not stop to ask questions."

"Why not swing a white light at 'em, then?"

"That's a good idea, too!" agreed Ned. "If they seem to be heading toward us, just get a white flag going."

"They are not showing any light at all," announced Jimmie. "They're just sneaking along like an express train."

"Let us know at once if anything happens," Ned responded, turning back to his patient.

The boys had not long to wait.

Out of the gathering darkness Jimmie saw a burst of flame which lighted up a portion of the approaching steamer. A bright flash in a wave some distance in advance of the "U-13" next attracted his attention. The sharp roar of a cannon came to the ears of all.

"Are they shooting at us?" asked Ned, again approaching the ladder.

"Don't know!" Jimmie replied briefly. "I saw the flash and heard the noise. There was a splash some distance ahead of us in the water. Maybe they can't aim straight."

Ned mounted the rungs of the ladder without further delay. He closed his eyes as he did so, the better to accommodate his vision to the change from the light below to the darkness outside. In a moment he was peering in the direction indicated by Jimmie.

"Can you make her out?"

"Yes," replied Ned. "I can just see a sort of thick place in the darkness. My eyes will be all right soon."

"I don't believe they were shooting at us at all!" commented Jimmie, musingly. "They can't see us!"

As if to disprove this statement, another flash lighted up the forward portion of the other vessel.

Ned grasped Jimmie's arm and pointed straight ahead.

Skipping from wave to wave, throwing up a fountain of spray from each, the shot from the steamer plowed its way across the path of the "U-13,"

pa.s.sing so close that the boys were struck by the flying drops of water.

"That means that we are to stop!" declared Ned. "Next time they'll shoot _at_ us!"

"And hit us, too!" excitedly put in the other.

Without waiting for orders from Ned, the lad leaned over the coaming of the little hatch.

"Shut her off, Jack!" he cried. "Back on your engines. That guy thinks we are Germans!"

Jack at once complied with the request, and soon the "U-13" was gently rolling in the trough of the sea.

Frank sprang from the wheel to the ladder, mounting to the deck just as a beam of flame from a powerful searchlight aboard the steamer swept the "U-13" from end to end.

In the glare of the light the three boys stood plainly visible. They could not, however, distinguish the details of the other vessel because of the flaming eye regarding them with unwinking stare.

For a few moments they stood close to each other, uncertain what to do.

At length a voice hailed them.

"Submarine, ahoy! What vessel is that?"

"Shall I tell them our name?" asked Ned anxiously.

"No," urged Jimmie. "Don't say 'U-13'!"

"They've seen it on the side, anyhow!" scorned Frank.

"Don't let them think we're Germans. Don't you see they're English?"

queried Jimmie.

"It doesn't signify they're English, even if they do speak the language,"

returned Ned. "Can't you answer?"

"Ahoy, there!" came an impatient voice.

"Steamer, ahoy!" replied Ned. "We're a peaceful submarine manned by neutral noncombatants!"

"A likely yarn, indeed!" laughed the stranger. "Stand by to receive a boat. I shall send an officer aboard to investigate."

"All right, Captain," consented Ned. "Glad to meet you!"