Del Mar threw on a switch. The submarine hummed and trembled. Slowly she sank in the harbor until she was at the level of the underwater entrance through the rocks. Carefully she was guided out through this entrance into the waters of the larger, real harbor.

Del Mar took his place at the periscope, the eye of the submarine.

Anxiously he turned it about and bent over the image which it projected.

"There it is," he muttered, picking out Arnold's yacht and changing the course of the submarine so that it was headed directly at it, the planes turned so that they kept the boat just under the surface with only the periscope showing above.

Forward, about the torpedo discharge tubes men were busy, testing the doors, and getting ready the big automobile torpedoes.

"They must have seen us," muttered Del Mar. "They've started the yacht.

But we can beat them, easily. Are you ready?"

"Yes," called back the men forward, pushing a torpedo into the lock-like compartment from which it was launched.

"Let it go, then," bellowed Del Mar.

The torpedo shot out into the water, travelling under her own power, straight at the yacht.

Elaine and I looked back. The periscope was much nearer than before.

"Can we outdistance the submarine?" I asked of Arnold.

Arnold shook his head, his face grave. On came the thin line of foam.

"I'm afraid we'll have to leave the yacht," he said warningly. "My little motor-boat is much faster."

Arnold shouted his orders as he led us down the ladder to the motor-boat into which we jumped, followed by as many of the crew as could get in, while the others leaped into the water from the rail of the yacht and struck out for the sh.o.r.e which was not very distant.

"What's that?" cried Elaine, horrified, pointing back.

The water seemed to be all churned up. A long cigar-shaped affair was slipping along near enough to the surface so that we could just make it out--murderous, deadly, aimed right at the heart of the yacht.

"A torpedo!" exclaimed Arnold. "Cast off!"

We moved off from the yacht as swiftly as the speedy little open motor-boat would carry us, not a minute too soon.

The torpedo struck the yacht almost exactly amidships. A huge column of water spurted up into the air as though a gigantic whale were blowing off. The yacht itself seemed lifted from the water and literally broken in half like a brittle rod of gla.s.s and dropped back into the water.

Below in the submarine, Del Mar was still at the periscope directing things.

"A hit!" he cried exultingly. "We got the whole bunch this time!"

He turned to the men to congratulate them, a smile on his evil face.

But as he looked again, he caught sight of our little motor-boat skimming safely away on the other side of the wreck.

"The deuce!" he muttered. "Try another. Here's the direction."

Furiously he swore as the men guided the submarine and loaded another torpedo into a tube. As the tube came into position, they let the torpedo go. An instant later it was hissing its way at us.

"See, there's another!" I cried, catching sight of it.

All looked. Sure enough, through the water could be seen another of those murderous messengers dashing at us.

Arnold ran forward and seized the wheel himself, swinging the boat around hard to starboard and the land. We turned just in time. The torpedo, brainless but deadly, dashed past us harmlessly.

As fast as we could now we made for the sh.o.r.e. No one could catch us with such a start, not even the swiftest torpedo. We had been rescued by Arnold's quick wit from a most desperate situation.

Somewhere below the water, I could imagine a man consumed with fury over our escape, as the periscope disappeared and the submarine made off.

We were safe. But, looking out over the water, we could not help shuddering at the perils beneath its apparently peaceful surface.

CHAPTER XIV

THE LIFE CHAIN

Early one morning, a very handsome woman of the adventuress type arrived with several trunks at the big summer hotel, just outside the town, the St. Germain.

Among the many fashionable people at the watering-place, however, she attracted no great attention and in the forenoon she quietly went out in her motor for a ride.

It was Madame Larenz, one of Del Mar's secret agents who, up to this time, had been engaged in spying on wealthy and impressionable American manufacturers.

Her airing brought her, finally, to the bungalow of Del Mar and there she was admitted in a manner that showed that Del Mar trusted her highly.

"Now," he instructed, after a few minutes chat, "I want you to get acquainted with Miss Dodge. You know how to interest her. She's quite human. Pretty gowns appeal to her. Get her to the St. Germain. Then I'll tell you what to do."

A few minutes later the woman left in her car, so rapidly driven that no one would recognize her.

It was early in the afternoon that Aunt Josephine was sitting on the veranda, when an automobile drove up and a very stylishly gowned and bonnetted woman stepped out.

"Good afternoon," she greeted Aunt Josephine ingratiatingly as she approached the house. "I am Madame Larenz of New York and Paris.

Perhaps you have heard of my shops on Fifth Avenue and the Rue de la Paix."

Aunt Josephine had heard the name, though she did not know that this woman had a.s.sumed it without being in any way connected with the places she mentioned.

"I'm establishing a new sort of summer service at the better resorts,"

the woman explained. "You see, my people find it annoying to go into the city for gowns. So I am bringing the latest Paris models out to them. Is Miss Dodge at home?"

"I think she is playing tennis," returned Aunt Josephine.

"Oh, yes, I see her, thank you," the woman murmured, moving toward the tennis court, back of the house.

Elaine and I had agreed to play a couple of games and were tossing rackets for position.

"Very well," laughed Elaine, as she won the toss, "take the other court."