"You mean the one you met on the other side of the bay-a Mr. James?"

"I haven't seen him since, and he was going to bring the bell for me to look at," A. H. reported. "Now I'm afraid maybe I'll never see him again, and I believe he has something I've been hunting for all over the country."

"Not the jeweled bell?" Nancy asked excitedly.

"Mr. James didn't tell me much, but I have a sneaking suspicion that it might be," Mr. Hendrick confided.

Nancy was startled at the information. She felt certain that Mr. James, alias Harry Tyrox, had not obtained the jeweled bell by honest means. Perhaps he did not even have it, but knew where it was and was trying to get hold of it. This might account for his not contacting A. H. again.

"Unless the reason is that he has left this part of the country permanently," she thought.

Nancy hoped this was not so, and asked the bell collector to let her know the minute he heard from Mr. James. Then she inquired what kind of a tone the jeweled bell had.

"Oh, a very pleasant musical sound, almost like one in the middle register of a set of chimes."

"Then your lost bell couldn't possibly be the one in Bald Head Cave?"

"Oh, no, that one has a deep tolling sound." A. H.'s eyes brightened. "I'd give a lot to get my hands on it just the same," he declared, "but I value my life too much. Can't figure a way to keep from drowning, or you can bet your last dollar I'd be inside that cave this minute!"

"Perhaps I can help you," Nancy said.

While Mr. Hendrick listened with rapt attention, she told him of her theory that the cave was flooded for only a few hours each day, and that the period of danger could be clocked accurately.

"Say! Maybe I'll go there sometime!" the man exclaimed. "You really think it's safe?"

"I have an idea that if a person doesn't venture into the cave after the tide has started to come in, he won't be trapped by the rushing water. I'll let you know later."

Because Mr. Hendrick was so pleased at the information she had given him, he talked more freely while he ate his lunch. As she served his dessert, he surprised her by saying:

"I've been thinking things over since I've been sitting here. I have a hunch that man James may be mixed up with the thief who has the jeweled bell."

"What makes you think that?" Nancy asked, trying not to show her eagefness to hear his answer.

"Didn't I tell you I traced it to a son of the original thief? His name is Grumper. He's an ornery little fellow-extraordinarily short. Haven't actually seen him, but I've been told he's around here."

"You think Grumper still has the bell after all these years? Wouldn't he have been tempted to sell it, or at least the jewels?"

"Not Grumper. He's a strange sort of man, not much concerned with money. They tell me chemistry is his main interest in life. He got into a jam with the company where he worked, and disappeared. I've good reason to think he's skulking around here somewhere."

"How did you learn Grumper had the bell?" Nancy asked curiously.

"From that note found in my father's possessions. You saw only part of the message."

Nancy would have asked Mr. Hendrick more questions, and found out his address, but just then another customer sat down at a nearby table. A. H. immediately became silent. He left the tearoom before the young detective had an opportunity to talk with him again.

Later that day she and Ned went to the boat dock with the intention of renting a motorboat to do some further exploring at Bald Head Cave. There they learned that Amos Hendrick had taken a boat and gone alone to the cave.

"He may get into trouble there!" Nancy said anxiously. "I should have warned him not to enter the cave until I've had a chance to prove my theory about the tides. If I'm wrong, he may drown!"

"Then we must go after him, and we've no time to lose!" Ned declared.

When he and Nancy reached the base of Bald Head Cliff in the motorboat, they could find no trace of A. H. Had he ventured into the cave?

"Say, who is that up there on the cliff?" Ned asked suddenly. He pointed to a figure seated on the high rocks, peering intently at the couple through a telescope. He was not Mr. Hendrick, as George had thought when she and her friends had seen a man on the cliff with a telescope.

"He certainly looks familiar, though," Nancy remarked. "Why is he watching us?"

Her attention was distracted by a flash of white near the cave entrance. Distinctly she saw a ghostly figure retreat into its dark interior. Within a few minutes a bell from within started to toll.

CHAPTER XVII.

Important Identification

"THE warning!" Nancy exclaimed. "Oh, what if A. H. is inside the cave!"

"If he is," Ned said grimly, "we're too late to save him!"

Fearfully he and Nancy watched as water began to boil from the entrance. A box floated clear, but to their relief, no body or overturned boat was washed from the cave.

Convinced that A. H. could not have been drowned by the rushing water, Nancy sighed in relief.

"Let's climb the cliff," she suggested, "and talk to the man with the telescope. He may be able to answer a lot of questions about this place."

Ned anch.o.r.ed the boat, and the couple waded ash.o.r.e. They climbed the rocks, using the path up which Nancy had gone before. But when they reached the top, the man had disappeared. They walked around a while, and peered into the cottage, but he did not return.

"Show me the place where you went to sleep that time," Ned suggested.

Nancy ran ahead, searching for the exact spot. When she thought she had located it, the young detective waited for Ned. Presently she began to feel dizzy. The blue sky above became misty, as if a film had dropped over her eyes. Vaguely she recalled that the same symptoms had overtaken her the first day she had visited the cliff.

"Ned!" she called in a weak voice. "Ned!"

He ran quickly toward her. One glance at Nancy's face told him something was seriously wrong.

"It's probably the climb," he said solicitously. "I'll carry you to the beach and you'll feel okay."

He lifted her from the ground and worked his way down the steep slope. By the time they reached the beach, Nancy seemed better.

"I don't know what came over me," she apologized, deeply embarra.s.sed. "I've never had spells like this before!"

Ned insisted upon their going home at once so she could rest. But after he had left Mrs. Chantrey's, Nancy subjected herself to a severe athletic test. She raced up- and downstairs four times without pausing. George and Bess, who entered the house, stared at her in amazement.

"I'm not crazy!" Nancy said, laughing. "I'm only trying to determine if I get fainting or dizzy spells after strenuous exertion."

"You could be a star athlete!" George retorted. "Why, you're not even breathing very hard."

"I feel fine!" Nancy laughed. "This test certainly proves I'm all right. But there was something queer about the way I nearly fainted today while on Bald Head Cliff! When I was up there I became very drowsy-almost as if I'd been drugged!"