CHAPTER XXIII--THE TREMBLING NOISE

  Jack, Walter, and Paul tore away more of the bushes screening the mouthof the natural cave. As they removed the leafy branches the black holewas seen to be of large size, fully high enough to permit even a tallman to enter without stooping, and wide enough to enable three to walkabreast.

  "This is some cave!" exclaimed Jack. "I wonder Mr. Floyd never told usabout it."

  "Perhaps he didn't know," suggested Cora. "I wouldn't have seen it, andI was within a few feet of it, if I hadn't slipped and pulled away thebush."

  "Well, we'll soon see if it amounts to anything," declared Paul, settingdown the pail of berries he was carrying.

  "Are you girls coming in with us?" asked Walter, looking at Cora and herchums who had not advanced.

  "I don't know. Shall we?" asked Hazel, looking at her brother.

  "I don't want to stay here," said Cora. "Besides, something might happento the boys. But how are you going to explore the cave in the dark? Andit is as dark as a bottle of ink in there. Have any of you yourflashlights?"

  "We can make a torch of wood," said Jack, when it developed that none ofthem had one of the pocket electric lights.

  But just as Jack and the others were about to enter the cave themutterings of thunder which had been increasing, culminated in such aclap that the girls, involuntarily placed their hands over their ears.

  "Come on! Run for the bungalow!" cried Cora. "Else we'll be caught in aterrible storm! It's starting to rain now."

  Some hot drops hissed down, the prelude to an almost tropical fury ofthe elements it seemed.

  "We can go into the cave," suggested Paul.

  "No!" cried his sister. "You shan't go in there with this storm comingup. The cave will keep. Come on, let's run!"

  She darted off down the side of the mountain, the other girls following.The boys hesitated a moment, and then, not wishing to desert the girls,even though the latter ran first, they followed.

  "We can come back to the cave to-morrow," said Walter. "It won't runaway. And to explore it well we ought to have the electric lights. Comeon."

  Paul and Jack followed him, and they all reached the girls' bungalowjust as the deluge of rain came down.

  For an hour or more the storm raged, blinding lightning and deafeningthunder succeeding one another. But the bungalow was snug and safe,though once, when a tree was struck not far away, the girls screamed interror.

  That crash, however, seemed to be the culmination of the outburst, forfrom then on the rain began to slacken, and the thunder died away inmuttered rumblings and the lightning became paler and paler until it wasonly a faint, shimmering light.

  Then the dark sky cleared and the sun came out, shining through thestorm-riven clouds and warming the ground and trees which were drippingfrom the vigorous bath.

  "We got home just in time," commented Cora, as they looked out on theceasing storm. "A little longer on the mountain and we would have beendrenched."

  "That cave was a find," commented Jack. "I want to see what's in it."

  "Probably nothing more than a hole in the side of the mountain,"commented Bess.

  "I wouldn't be too sure of that," voiced Walter. "I wonder if Mr. Floydknows anything about it?"

  It developed that the caretaker did not, though he said there wereseveral small mountain caves in that section, and this was probably oneof them that he had not chanced upon.

  "Do you think smugglers or pirates might have used it?" asked Hazel,with a smile.

  "Hardly pirates," commented Jack. "Too far from the water. But smugglersmight have done so. We're not so far from the Canadian line."

  "All bosh!" declared Paul. "It's probably a garage dating from the stoneage when the early inhabitants used the dinosaur as a jitney!"

  They all laughed at his conceit and talked further of the cave and whatthey might find in it when they explored it the next day.

  Whether it was the severe thunderstorm, or whether it was theculmination of the happenings of the past few weeks was not made clear,but it was certain that the girls, even Cora, were more nervous thanthey had been at any time yet.

  "I--I wish we didn't have to stay here to-night," said Belle when supperwas over, and they sat out on the porch, gazing into the fast-gatheringdarkness.

  "Why?" asked Cora.

  "Because I--I'm afraid. Come now, aren't you?" she challenged.

  "Well, I can't say I like all the mysterious happenings," Cora admitted."And now that we know there is a cave near us--more than one perhaps--andthat we don't know who--or what--may be in them, why, I can't say it isthe most pleasant vacation we have experienced."

  "This bungalow gives me the creeps!" complained Hazel.

  "Why not take ours?" suggested Walter. "It's large enough for you tosleep in, and we'll take this one. Come on, what do you say?"

  "No, not to-night anyhow," decided Cora. "We'll keep to our agreementand stay here. Mrs. Floyd will be here with us."

  "And not Mr. Floyd?" asked Belle.

  "No, not until later. He has to go to some town meeting I believe, andwill come in around midnight. But nothing has happened in the last fewdays--not even a noise."

  "I've heard noises," confessed Belle.

  "What sort?" Jack inquired.

  "Oh, sort of rumbling, trembling noises, and they seemed to be away downunder the ground. I heard one yesterday, when I came back to get my veilafter the others had gone out. It scared me," Belle added.

  "I think the waterfall causes those rumbling noises," said Walter."We'll have to investigate that to-morrow."

  The boys went to their own bungalow, and Mrs. Floyd came in to occupythe small temporary bedroom. Her husband would be in later, sheexplained, confirming Cora's information in that respect. Thethunderstorm had cooled the rather oppressive air and there was arefreshing breeze blowing as the girls went up to their bedrooms.

  Just who awakened first, it would be hard to say. Probably it was Belle,as she was the lightest sleeper. Cora heard her calling, and at the sametime she was aware of another disturbance.

  "Do you hear it?" asked Belle from her room.

  "Yes," Cora answered. At the same time she could hear Bess and Hazelgetting up.

  The whole bungalow seemed filled with a roaring, trembling noise, andthere was a slight vibration of the building.

  "What is it? Oh, what is it?" cried Belle, in hysterical tones.

  "I don't know," answered Cora. "But I'm going to find out."

  "How?"

  "By calling the boys. Mrs. Floyd, are you awake?" Cora demanded, goingto the head of the stairs.

  "Yes. That noise awoke me."

  "Is Mr. Floyd home?"

  "Not yet."

  "Then I'm going to telephone for the boys!"