"That's all right," announced Belle, "but suppose-suppose they come in the night, when we're asleep, and take one of us?"

"Let them begin on Bess," suggested Jack, with a laugh. "No offense, of course, fair one," and he bowed, "but you know you could give a good account of yourself if some one did try to walk off with you."

"Don't dare suggest such a thing!" cried the plump twin. "I'd never go to sleep if I thought they'd come at night."

"They do seem to confine their visits to daytime, and to the periods when we are away," said Cora.

"Which makes it look, more than ever, as if they watched the bungalow and knew just when to take advantage of our absence," commented Paul.

"Oh, don't say that!" begged Belle. "Just think-they-they may be watching now!"

"Well, if they are let's go and see if we can rout them out," suggested Jack. "There aren't many places of concealment about the bungalow."

While the other girls helped Cora and Hazel put to rights the upset rooms, the boys made a thorough search outside. There did not seem to be any place where the mysterious persons might conceal themselves in order to spy on the bungalow. There were trees all about, but the underbrush had been cut away, and there was small chance for concealment. The boys also started to make an inspection about their own bungalow, but this was cut short by a shower that came up.

"Well, so far, we are just about where we started," said Jack, as he and his two chums were eating supper with the girls that night. "We haven't found out anything."

"But we will!" declared Cora. "I'm not going to be beaten this way.

We'll organize a campaign."

They talked to this end, making a tentative plan that the next time they went off on a trip, some member of the party would be left behind in concealment in the bungalow, to see, if possible, who the visitor or visitors were.

"And if that doesn't work we'll try something else," said Walter.

It was evident, though, that after the first few trials the new plan was not going to work. Though the boys took turns in remaining in concealment while the others went away, not a sound or sign of disturbance was noted. No furniture was misplaced, and nothing was taken.

"We've got to have a new scheme," said Cora. "Let's talk to Mr. and Mrs.

Floyd about it. Maybe they can suggest something."

But the caretaker and his wife had nothing to offer. They were as much worried and disturbed by the queer happenings as were the girls and boys. And though they were generous and kindly souls, they were not quick thinkers, and had little imagination.

"It's just spirits," said Mrs. Floyd. "Spirits come and go."

"There aren't any such things," declared Cora.

"Maybe it's lightning," suggested Mr. Floyd. "We have pretty heavy thunderstorms up here."

"Lightning can't move furniture, nor carry off looking gla.s.ses and hair ribbons," Cora went on.

"Well, once lightning struck Jim Dobson's cabin," the caretaker said, "and knocked all his pots and pans off the stove, and burned a hole right through his clock."

"That's within the bounds of possibility," admitted Jack.

"It's boys!" decided Walter. "You'll find that some youngsters are up to these tricks, and they're cute enough to cover up their tracks."

"That's it," said Paul. "They're too cute. They don't leave any tracks.

How they get in and out again, without leaving a clew or a mark is more than I can see." For an examination of the place after the losses suffered by Cora and Hazel had disclosed no apparent means of egress or ingress.

One evening when the girls had gone over to the boys' bungalow to sit and talk, Cora, who had gone to the end of the porch, whence a view could be had of the other building, uttered an exclamation.

"There's a light in our bungalow!" she called. "Did we leave one burning?"

"No," answered Belle. "I put it out, as I was afraid of fire."

"Well, one's there now. See how it dances about!"

Indeed, a light could be observed, dancing up and down, flashing first from one window and then from another.

"It's Mr. or Mrs. Floyd," said Jack.

"They've gone to the village," Paul said. "I saw them go."

"It's the mysterious visitors!" cried Walter. "They're using Cora's flashlight! Come on, boys, this time we have them!"

He ran toward the bungalow, followed by the others.

CHAPTER XXII-A MOUNTAIN CAVE

Advancing rapidly toward the girls' bungalow, where so many strange happenings had occurred, and where even now the strange light was flashing, first at one window, then at another, Cora and her chums-boys and girls-speculated on what could be the cause.

"Let the boys go first," cautioned Belle. "We don't know what it might be."

"That's right! Wish the danger on to us!" commented Jack. "But we're not afraid."

"It's only those mischievous boys," declared Paul. "We'll catch 'em in the very act now."

"But how did the little rascals get in without our seeing them?" asked Walter.

"We weren't watching the bungalow very closely," said Paul. "They could easily have slipped in from the back, around on the forest side. They watched their chance."

"But what's their game?" asked Jack, as they crossed the rustic bridge on the run, their footsteps echoing dully on the boards.

"Go easy!" cautioned Walter. "Don't make so much noise, or we'll scare them away before we have a chance to catch them."

"They can't hear us above the noise of the waterfall," declared Jack.

"But what's their game? That's what I want to know. Why are they flashing that light about so?"

"There must be two or three of them with lights," said Cora. "For first I noticed it up in the window of my room, and a second later, certainly in less time than any human boy could make the trip downstairs, the light showed from a window in the living room."

"Probably there are three or four of the little rascals," said Walter.

"Come on now, we're almost there."

"Wait here, girls," suggested Cora. "Let the boys go ahead, though after they catch these mischief-makers I'll feel like giving them a good shaking myself."

Walter, Paul and Jack advanced toward the bungalow. They went softly up on the porch, looking sharply for a sign of the light.