Kane remained like a statue in his chair, staring at the detective. The suggestions thrown out by Nick Carter concerning Count Cadillac paralyzed him, so to speak. He was appalled by it, and—he could not bring himself to the belief that there was anything in it more than that strange circumstance which he had described in the beginning as circumstance. And yet, all the while, he was forced to admit to himself that there were suspicious circumstances.

Suddenly, without a word of his intention, but being already garbed in his bathing-suit, he kicked off the sandals he wore, leaped to his feet, reached the side of the yacht with one bound, and dived into the water.

Just as he poised on the rail, he shouted to the detective to “come on,” and so he had scarcely disappeared in the water before Nick was after him. But when Nick Carter dived he did not come immediately to the surface, as did Maxwell Kane. The moment he was underneath the surface he turned toward the bow of the yacht, and, continuing under the water, he passed under the vessel’s bow to the port side before coming to the top again for air.

After a moment he heard Kane calling, and, not wishing to frighten his host, he answered.

[50]

“Come along forward, Max,” he called. “I have a suggestion to make.”

“Well, what is it?” asked Kane, when he appeared.

“As nearly as I can determine from the description you have given me, the yacht is lying in relatively the same position she occupied when the pirate came aboard of her, is she not? Isn’t she headed about the same?”

“I should say that she could not be put more exactly in the same spot,” replied Max.

“In that case,” said Nick, pointing with his finger, “the pirate craft should have been lying about yonder—so, while Captain Sparkle was giving you his original impersonation of Hamlet.”

“Yes; her bow must have been about yonder, and her stern out there”—indicating with gestures the positions he described.

“And when Sparkle and his men went over the side from the yacht to their own craft, where is the point where they did that?”

“Right here—directly over our heads.”

“When the pirate craft left you, she must have gone in that direction,” continued the detective, pointing toward the Sound.

“Yes, that is about it.”

“All right. Thank you.”

Nick had been clinging to the bowsprit-stay while he was talking; but now, without more remarks, he released his hold upon it and permitted himself to sink slowly into the depths.

Kane happened to be looking away from him at that[51] moment, and he continued, through several sentences, his description of how the pirate had sailed out of the harbor into the open Sound, where she had finally disappeared. Perceiving, presently, that his description was not received with the enthusiasm he had a right to expect, he turned his head, and for the first time discovered that the detective was no longer there.

Kane was a strong swimmer, but was not overfond of diving, and so, instead of pursuing the detective, who he expected had merely gone under the vessel in order to reach the other side, he swam away lustily toward the stern, and climbed upon the deck again, where he seated himself under the shade of the awning.

But Nick Carter had not permitted himself to sink beneath the water merely for the purpose of disappearing in order to reappear again at another spot. In fact, his request for the bathing-suit, and for the opportunity to use it, had been with a well-defined motive other than the mere pleasure to be derived from a dip in the sea.

The detective really wished to examine the bottom of the cove. The idea did not occur to him because he believed that he would discover any suggestive trace of the pirate down there, but he put the thought into words because it was his professional habit never to neglect even the most trivial and apparently unimportant item from his investigations.

The idea of examining the bottom of the Sound for traces of a vessel which had passed over that spot would be absurdly ludicrous; but, all the same, there was one idea which had been suggested to Nick by the description[52] Kane had given him of the pirate craft, and he believed it to be more than possible that there might be an indication of the fact—if it were a fact—to be found at the bottom, not far from the buoy to which the yacht was moored.

It will be remembered that he asked Kane if he thought the pirate craft was a submarine, and it must be recorded that, notwithstanding the reply he received, he thought it more than probable that the silent approach of the vessel had been accomplished in that way.

Nick knew that the bottom of that cove was soft, and largely composed of clay, especially at points where it attained as great a depth as that where the yacht was moored.

Clay is impressionable. It will receive and hold the shape of an article which rests upon it a considerable time, and the detective argued that if the Shadow, as she was called, had at any moment rested upon the bottom at that particular point, she would have left her mark there. That she was a submarine, or at least was capable of diving beneath the surface and remaining there for some time, he had not a doubt. The very fact that she had approached the Goalong so silently that her proximity was not suspected was sufficiently satisfactory of that idea to him.

The water was, fortunately, unusually clear, and Nick had no difficulty in examining the bottom almost at his leisure. When he came to the surface again, and climbed up on the deck to a seat beside his friend, he remarked:

[53]

“Well, Max, it is as I thought. Your pirate craft is some sort of a submarine.”

“Is she? How do you know that? Have you seen her?”

“Well, not exactly.”

“I didn’t know but that was why you stayed under water so long. I thought maybe you had gone after her.”

“Well, you weren’t far wrong, at that. I figured that if she could dive, that was pretty nearly the explanation of how she approached you so silently, and, following up that idea, I decided that if she did dive, she must have left a mark of some kind on the bottom not far from that buoy.”

“And you found one, eh?”

“Yes, I found one.”

“What was it?”

“Merely the impression of her keel in the clay at the bottom.”

“And I suppose that from that impression, which would mean nothing at all to me, you have read enough facts about the pirate to fill quite a respectable book, eh?”

Nick laughed.

“No, Max,” he said. “For once you are wrong, and for once I did not find anything more than you would have discovered had you gone there in my place. All I know from what I saw there is that a vessel’s keel has rested on the bottom within the last twenty-four hours. I could tell, of course, approximately, her length,[54] and from that could make a good guess at her breadth of beam, but you have already done that for me. Now, old chap, let’s get into our clothes.”

Fifteen minutes later, they were reclothed and seated again in their favorite chairs under the awning.

“And now, Nick, what next?” asked Kane.

“First, tell me what yacht is that one, heading in here toward the anchorage?” replied Nick, pointing over Kane’s shoulder.

“Oh, that? She is Burton’s auxiliary, the Harkaway,” replied Kane. “There will be half a dozen more of them in here before sundown. There is a regular meeting of the club to-night, and I shouldn’t wonder if there would be a score or more of yachts in here between now and midnight.”

“If the pirate only knew that, it might prove to be a harvest for him, don’t you think?” asked Nick.

“Oh, I don’t know about that. There would be too many of them for him, wouldn’t there?”

“Not if he is a submarine, and he is one. And say, Max, that thought suggests a question.”

“What is it?”

“Does the count happen to know about that meeting?”

“What meeting? Oh, you mean the club meeting?”

“Certainly. You just referred to it.”

“Why, yes. I suppose he knows about it. He has heard me say that I wished to be at the meeting to-night.”

“So he also knows that there will be a lot of craft at[55] this anchorage to-night, and that the owners and guests from them, almost to an individual, will be ashore at the club-house, doesn’t he?”

“I have never regarded him as a fool, Nick, and he would have to be pretty near one if he didn’t know that.”

“And I suppose, Max, that you are looking forward to creating a sensation when you tell the bunch about how you were boarded by a pirate and robbed like a gentleman, eh?”

“Why, yes——”

“It is too bad to take that privilege from you, old man, but I really wish you would say nothing whatever about it, and that you would caution your wife and guests to observe the same silence. I will only hold you to that for to-night. To-morrow you can tell the whole world about it if you like.”

“But why so mighty secret about it to-night, Nick?”

“Because, Max, I expect that the pirate will make another call on the fleet to-night. It would be a splendid time for him to come; and if he happens to have any idea of putting in an appearance, I would rather not have the whole bunch of owners and their friends rush to their vessels from the club-house, after hearing your story, just in time to spoil the pirate’s plans. I would rather he’d have the coast clear for to-night, if he does intend to come, and if you yapped about the business the scene might be spoiled.”