"Then we shall transfer our activity to the Yacht Club to-night," was all that Kennedy vouchsafed.
CHAPTER VI
THE TRIPLE MIRROR
It was the regular Saturday night dance at the club, a brilliant spectacle, faces that radiated pleasure, gowns that for startling combinations of color would have shamed a Futurist, music that set the feet tapping irresistibly—a scene which I shall pass over because it really has no part in the story.
The fascination of the ballroom was utterly lost on Craig. "Think of all the houses only half guarded about here to-night," he mused, as we joined Armand and McNeill on the end of the dock. I could not help noting that that was the only idea which the gay, variegated, sparkling tango throng conveyed to him.
In front of the club was strung out a long line of cars, and at the dock several speed boats of national and international reputation, among them the famous Streamline II, at our instant beck and call. In it Craig had already placed some rather bulky pieces of apparatus, as well as a brass case containing a second triple mirror like that which he had left with Armand.
With McNeill, I walked back along the pier, leaving Kennedy with Armand, until we came to the wide porch, where we joined the wallflowers and the rocking-chair fleet. Mrs. Verplanck, I observed, was a beautiful dancer. I picked her out in the throng immediately, dancing with Carter.
McNeill tugged at my sleeve. Without a word I saw what he meant me to see. Verplanck and Mrs. Hollingsworth were dancing together. Just then, across the porch I caught sight of Kennedy at one of the wide windows. He was trying to attract Verplanck's attention, and as he did so I worked my way through the throng of chatting couples leaving the floor until I reached him. Verplanck, oblivious, finished the dance; then, seeming to recollect that he had something to attend to, caught sight of us, and ran off during the intermission from the gay crowd to which he resigned Mrs. Hollingsworth.
"What is it?" he asked.
"There's that light down the bay," whispered Kennedy.
Instantly Verplanck forgot about the dance.
"Where?" he asked.
"In the same place."
I had not noticed, but Mrs. Verplanck, woman-like, had been able to watch several things at once. She had seen us and had joined us.
"Would you like to run down there in the Streamline?" he asked. "It will only take a few minutes."
"Very much."
"What is it—that light again?" she asked, as she joined us in walking down the dock.
"Yes," answered her husband, pausing to look for a moment at the stuff Kennedy had left with Armand. Mrs. Verplanck leaned over the Streamline, turned as she saw me, and said: "I wish I could go with you. But evening dress is not the thing for a shivery night in a speed boat. I think I know as much about it as Mr. Verplanck. Are you going to leave Armand?"
"Yes," replied Kennedy, taking his place beside Verplanck, who was seated at the steering wheel. "Walter and McNeill, if you two will sit back there, we're ready. All right."
Armand had cast us off and Mrs. Verplanck waved from the end of the float as the Streamline quickly shot out into the night, a buzzing, throbbing shape of mahogany and brass, with her exhausts sticking out like funnels and booming like a pipe organ. It took her only seconds to eat into the miles.
"A little more to port," said Kennedy, as Verplanck swung her around.
Just then the steady droning of the engine seemed a bit less rhythmical. Verplanck throttled her down, but it had no effect. He shut her off. Something was wrong. As he crawled out into the space forward of us where the engine was, it seemed as if the Streamline had broken down suddenly and completely.
Here we were floundering around in the middle of the bay.
"Chuck-chuck-chuck," came in quick staccato out of the night. It was Montgomery Carter, alone, on his way across the bay from the club, in his own boat.
"Hello—Carter," called Verplanck.
"Hello, Verplanck. What's the matter?"
"Don't know. Engine trouble of some kind. Can you give us a line?"
"I've got to go down to the house," he said, ranging up near us. "Then I can take you back. Perhaps I'd better get you out of the way of any other boats first. You don't mind going over and then back?"
Verplanck looked at Craig. "On the contrary," muttered Craig, as he made fast the welcome line.
The Carter dock was some three miles from the club on the other side of the bay. As we came up to it, Carter shut off his engine, bent over it a moment, made fast, and left us with a hurried, "Wait here."
Suddenly, overhead, we heard a peculiar whirring noise that seemed to vibrate through the air. Something huge, black, monster-like, slid down a board runway into the water, traveled a few feet, in white suds and spray, rose in the darkness—and was gone!
As the thing disappeared, I thought I could hear a mocking laugh flung back at us.
"What is it?" I asked, straining my eyes at what had seemed for an instant like a great flying fish with finny tail and huge fins at the sides and above.
"'Aquaero,'" quoted Kennedy quickly. "Don't you understand—a hydroaeroplane—a flying boat. There are hundreds of privately owned flying boats now wherever there is navigable water. That was the secret of Carter's boathouse, of the light we saw in the air."
"But this Aquaero—who is he?" persisted McNeill.
"Carter—Wickham—Australia Mac?"
We looked at each other blankly. No one said a word. We were captured, just as effectively as if we were ironed in a dungeon. There were the black water, the distant lights, which at any other time I should have said would have been beautiful.
Kennedy had sprung into Carter's boat.
"The deuce," he exclaimed. "He's put her out of business."
Verplanck, chagrined, had been going over his own engine feverishly. "Do you see that?" he asked suddenly, holding up in the light of a lantern a little nut which he had picked out of the complicated machinery. "It never belonged to this engine. Some one placed it there, knowing it would work its way into a vital part with the vibration."
Who was the person, the only one who could have done it? The answer was on my lips, but I repressed it. Mrs. Verplanck herself had been bending over the engine when last I saw her. All at once it flashed over me that she knew more about the phantom bandit than she had admitted. Yet what possible object could she have had in putting the Streamline out of commission?
My mind was working rapidly, piecing together the fragmentary facts. The remark of Kennedy, long before, instantly assumed new significance. What were the possibilities of blackmail in the right sort of evidence? The yeggman had been after what was more valuable than jewels—letters! Whose? Suddenly I saw the situation. Carter had not been robbed at all. He was in league with the robber. That much was a blind to divert suspicion. He was a lawyer—some one's lawyer. I recalled the message about letters and evidence, and as I did so there came to mind a picture of Carter and the woman he had been dancing with. In return for his inside information about the jewels of the wealthy homes of Bluffwood, the yeggman was to get something of interest and importance to his client.
The situation called for instant action. Yet what could we do, marooned on the other side of the bay?
From the Club dock a long finger of light swept out into the night, plainly enough near the dock, but diffused and disclosing nothing in the distance. Armand had trained it down the bay in the direction we had