"But about the cave," insisted Fenn.

"It sounds almost like a dream," went on Ruth. "One day, when I was walking through the woods around here, just before daddy and I took that automobile trip East, I was on a ledge of the cliff, about opposite where you were in the lake to-day. That particular ledge is not there now, as a landslide carried it away, but it was quite large, and easy to get to, when I was on it. I was after some peculiar flowers that grew there.

"As I was gathering them I saw an opening in the cliff, and I could look right into a large cave. I was so surprised I did not know what to do, and, much more so, when I saw several men at work. They seemed to be taking stuff out--valuable stuff, for they were very careful with it. I must have made some noise, for one of the men came to where I was looking in.

"He was very angry, and tried to grab me. I drew back, and nearly toppled off the ledge into the lake. Then the man threatened me. He said if I ever told what I saw something dreadful would happen to me.

"I was much frightened, and hurried away. I was going to tell my father of what I had seen, but the memory of the man's threat prevented me. The thing got on my mind so I was taken ill. Then came the automobile trip and the accident. But I could not forget the cave. It seemed like a bad dream, and it followed me. I did not know I had mentioned it in my delirium at your house, until you told me. Then I was frightened lest something happen to you, as well as to myself, and I begged you never to refer to it. But I could not forget it. All the while I kept wondering who those men were, and what they were taking out. I thought perhaps they might have found gold. Of course it was foolish, and, sometimes I think it was all only a bad dream. Only it is not a dream about poor daddy losing all his money."

"And it isn't any dream about that cave!" exclaimed Fenn, sitting up in bed. "It's real. There are men in it taking out something I think is valuable. They are doing it secretly, too. I don't know who it belongs to, but we'll soon find that out. By some curious chance I have discovered the same cave you looked into. I'll take you to it, and we'll see what those men are digging out. I'm going to get right up and go back there. I'm all right! We must go before the men take all the stuff! Where are the boys? Tell them to come here and help me dress."

"No, no!" exclaimed Ruth. "The doctor said you must be kept quiet!"

"I'm going to go back to that cave!" declared Fenn, and, getting out of bed, clad in a big bath robe, he began to hunt for his clothes, which, however were not in the room, having been taken to the laundry to be pressed.

"Mary! Mary!" called Ruth to the servant. "Telephone for the doctor.

Tell him Fenn is delirious!"

CHAPTER XXIX

A BAFFLING SEARCH

Fenn sat down rather suddenly on hearing Ruth make that announcement. He grew calm.

"All right," he said, good-naturedly, "there's no use alarming you. I'm not delirious. I never felt better in my life. That sleep I had was fine. My fever is all gone. But, go ahead, if you want to. Send for the doctor. I don't mind. I know what he'll say, and then I can go and hunt for that cave."

"Oh, Fenn, are you sure you're all right?" asked Ruth, much rea.s.sured by the cool manner in which the boy spoke.

"Sure. Here, feel of my pulse. It's as slow as yours."

Ruth did so, and, having had some experience in cases of illness, she realized that Fenn's fever had gone down.

"You do seem better," she acknowledged. "However, I think it would be a good thing for the doctor to see you. I don't want you to run any chances."

"All right," agreed Fenn.

The physician came again and said that, much to his surprise, Fenn's illness was not as alarming as had at first appeared.

"Can't I go out?" asked the lad, not telling what for.

"Hum--ah--er--um--well, it's a little risky, but then--well, I guess you can," and, after much humming and hawing the medical man gave his consent and left, shaking his head over the perverseness of those who were always in a hurry.

"Now send up my clothes, please," begged Fenn, when the doctor was safely away. "We'll solve the mystery of that cave in jig style."

"Hadn't we better wait for the other boys?" suggested Ruth. "Besides it's nearly dinner time, and you ought to eat something."

"Good idea," declared Fenn, but, whether it was the one about eating, or waiting for the boys he did not say.

Frank, Bart and Ned were rather late getting back from the motor boat ride, but they had such a good time that no one blamed them. Mr. Hayward also returned, and it was quite a merry party that gathered about the table. That is all except Mr. Hayward. He seemed to be rather worried over something, and, at times, was rather distracted, his thoughts evidently being elsewhere.

"What's worrying you, daddy?" asked Ruth, after a while.

"Nothing, my dear. Why?"

"You're not eating at all."

"I'm not very hungry. But come, we must go with Fenn and see if we can't help him locate that cave. I don't imagine we shall find anything of any account. Most likely the men were engaged in working an abandoned mine from which the prehistoric inhabitants took everything of value. Perhaps the men were those Chinese smugglers. I have telephoned word to the Government authorities about them, and some detectives may arrive any minute."

"Those men were not smugglers," declared Fenn. "They were taking something valuable from that mine, and they were so secretive about it that I'm sure they had no right to the stuff."

"Well, we'll soon see," declared Mr. Hayward.

"Where are we going to begin?" asked Bart.

"Let's go up to that hole, where we found Fenn's hat, and work down,"

suggested Ned.

"That's no good," declared the lad who had made the queer pa.s.sage. "That chute only comes out on the ledge, where the main shaft begins. If we could get to the ledge we'd be all right."

"I think we can get there without crawling or sliding down that dark, roped pa.s.sage," said Mr. Hayward. "But I was going to suggest that we take the motor boat and cruise along near where we picked Fenn up. If we found the opening in the cliff, from where he jumped, it would be easier.

It is rather difficult to get to the ledge."

"I think that's the best idea," remarked Frank.

"May I go with you, daddy?" asked Ruth, a bright flush of excitement coming into her cheeks.

"Maybe I can find the--" She stopped suddenly.

"I'm afraid not. There might be danger," said her father, not noticing her last remark.

"I'm not afraid."

"I wouldn't," said Fenn quickly. "Those men that I saw, didn't have any weapons, but they might be ugly customers, just the same."

"I think you had better remain at home, my dear," decided the girl's father, and, somewhat against her will, she consented, after a whispered conference with Fenn.

The others were soon in the motor launch, and were cruising along the lake sh.o.r.e, as near as possible to where Fenn had leaped into the water.

Narrowly they scanned the face of the cliff, for a sight of the opening from which Fenn had jumped. They went up and down for half a mile, in either direction, but there was no sign of it.

"Are you sure you jumped out of a hole, Stumpy?" asked Bart.

"Sure. I remember catching just a glimpse of that point of land before I went under water."

"Then the opening into the cave ought to be somewhere near here,"