Part 42 (1/2)

Meanwhile, another part of the strange mystery was being enacted with the girls as princ.i.p.al characters. They had entered farther into the secret pa.s.sage, beyond the queer swinging door which had closed after them.

”We're caught!” cried Belle. ”Oh, Cora!”

”Perhaps not,” said Jack's sister. ”If that door opened once for us it will do it again. But don't go back. Come on. We must see what is ahead of us. The boys will laugh if they hear we turned back when we had such a good opportunity.”

”Well, they shan't laugh at _me_!” declared Hazel. ”I'm with you, Cora.”

”And you may be sure we're not going to be left alone,” cried Bess.

”Come on, Belle!”

The latter hesitated a moment, looked back at the closed door, and then went forward. Their lamps made the place fairly light, and they could see that the pa.s.sage was planked here as it had been nearer the bungalow.

They had gone on perhaps fifty paces more and were wondering when the queer tunnel would come to an end, when Cora, who was walking in advance with Hazel, put her hand on her companion's arm, and cried:

”Do you hear it?”

”Hear what?”

”That strange, rumbling, trembling noise. Don't you _feel_ it?”

”Yes! Yes!” cried Belle. ”Oh, what is it?”

There was no doubt of the noise. It seemed to fill the whole pa.s.sage with a dull, rumbling roar, and the ground vibrated and trembled.

”Come on!” cried Cora, resolutely. ”It's just ahead of us. We will solve the mystery now!”

Willing or unwilling, Belle, Bess and Hazel followed their leader. With their electric lights showing the way the girls pressed forward.

Suddenly the pa.s.sage turned, and, making that turn, the girls came upon a strange sight.

Before them was an open door, which gave entrance to a large cave with rocky sides and roof. Vaulted and large the cave was, and from long wires fastened somewhere in the roof hung a number of incandescent lights. In the cave the girls saw several queer machines, and Cora, at least, recognized more than one of them as printing presses. A gasoline engine was throbbing away in one corner, and it was this, Cora decided, which made the rumbling, the throbbing and trembling vibrations.

Hardly realizing what they were doing, the girls walked forward, and, pa.s.sing through the open door, entered the cave which widened out at the end of the secret pa.s.sage.

”What-what does it all mean?” asked Bess.

Low as her voice was it seemed to awaken strange echoes in the vaulted cave. And at the sound of it something stirred in one corner. From a pile of boxes something arose-a something that resolved itself into an old man with white hair and a long, white beard. He peered from beneath his bushy white eyebrows, with piercing eyes at the startled girls, and from his throat came a guttural cry.

”Ah, ha! Police spies-four of 'em!” he snarled. ”I thought we'd be found out!”

With surprising quickness in one seemingly so aged the man slipped behind the girls. They turned, fearing an attack, but they need have had no alarm on that score. With a quick motion the old man closed and locked the door through which they had come.

”Now you're here-you'll stay!” he rasped out. ”On guard here, Bombee!

Hist! Watch 'em!”

And, as he called, a raw-boned, half-witted boy shuffled forward, and squatted, with a horrible grin, in front of the terrified girl prisoners.

CHAPTER XXIX-TO THE RESCUE