Two men entered the room shortly after the door had closed on the boys, and removed the handcuffs. They passed out in the same silent manner, and the prisoners were left alone again. There was no light in the room, but the moonbeams entered through the barred windows, and cast two streaks of light across the floor that was sufficient to enable the boys to see almost as well as by daylight. They each sat down dejectedly upon a bed and for a long time neither uttered a word. Harry was trying to think out the true meaning of their position, which began to assume a more serious phase to him. There was no element of play in it, now.

He reviewed his recent examination by General Serano, and wished he had not assumed quite so nonchalant an air, although he felt that he could not have answered the questions which would perhaps involve the safety of Captain Dynamite. They were unquestionably in a disagreeable situation. He realized that if he were to tell the entire truth they would be immediately released, but the truth would at once set the Spaniards on the heels of O'Connor, and Harry could not forget the personal risk the man had taken to save their lives after he had run them down, nor the kindness with which they, as unbidden guests on his ship, had been treated. To betray his confidence would be a dastardly act, for, even if he could have doubted the words of O'Connor, the actions of the commander of the gunboat were sufficient to indicate that it would go hard with the intrepid skipper of the Mariella if he should fall into the hands of the Spaniards.

Mason and Washington were still to be counted on. He felt sure that they would continue on their way to O'Connor and that he would make some move to effect their rescue. There was one strong objection to waiting for O'Connor. Whatever plan he might adopt for their relief must necessarily be attended by violence, for in no other way could he approach their captors, except it be by strategy, and there seemed to be no chance of escape in that way.

He feared for O'Connor's sake to take the consul into their confidence, except as a last resort. While he had the utmost respect for the man's integrity he feared the influence of General Serano. At all events there was nothing that could be done to-night. He turned to Bert who was sitting in an equally dejected frame of mind on the edge of his bed with his head in his hands.

"Let's turn in, Bert, old man. Things may be brighter in the morning."

"I don't see much hope. Do you think Captain Dynamite would care if we told that Spanish gentleman the whole truth as to how we came here?"

"No, I don't," replied Harry, indignantly. "If O'Connor could advise us I know the man well enough to believe that the first thing he would tell us to do would be to make a clean breast of everything. But I would hate to say what I should think of myself, or of you, if either of us did such a thing. Why man, you know as well as I do that it would set the Spaniards after him like a pack of hounds on the trail. And you know there is a price on his head and a big one, too. Don't let any more such bubbles get into your think tank or you and I will have to part company."

"You are right, Hal," said Bert, sheepishly. "I didn't think of the danger to him."

"Well, then, let's go to bed."

The boys threw off only their outer clothing and lay down on the hard husk mattresses and were soon fast asleep notwithstanding the uncertainty and danger of their predicament.

The place was in almost total darkness when Harry awakened suddenly and sat bolt upright in bed. He listened for a moment intently, as if for the repetition of the sound that had awakened him.

"What was it, I wonder. Something must have wakened me."

He sat motionless for a long time, but not a sound broke the stillness of the night.

"I know I heard something," he said to himself as he dropped back on the bed again. He could not sleep, however, for the sense that he had been awakened by a strange sound, and the mental effort that he had made to catch a repetition of it, had completely aroused him. He lay on his back looking up into the darkness when he heard a sound like a smothered sigh.

"Bert," he whispered, as he sprang up and sat on the edge of his bed, "was that you?"

"What's that? What's the matter, old man?" asked Bert, aroused from his sleep.

"Was that you?"

"Was what me—what's the matter with you, Hal?"

"Have you been awake?"

"No, not until you called me."

"Then you didn't sigh?"

"Not unless it was in my sleep."

"This wasn't a sleepy sigh."

"Say, Hal, what is the matter with you? You make me feel creepy."

"I heard a sigh."

Bert groped his way over to Harry's bed and sat down beside him.

"Say, old man, you're not asleep, are you?"

"No; Listen! There it is again."

The boys drew closer together and put out their hands until they touched one another. The sound they heard seemed to come from nowhere in particular.

"What do you think it is, Hal?"

"I don't know. Wait until we hear it again."

By this time their eyes had become accustomed to the darkness of the room, and aided by the star-lighted sky, they could see into every corner. There was no one in the room. Somewhat reassured they waited. The next time the sound was an unmistakable sob, and it seemed to be wafted through the barred windows on the still night air.

"I know what it is," said Harry, eagerly jumping from the bed and pulling the table under the window. "It's some one in the cell next to ours. Let's try to talk to him."

"He's probably a Spaniard or a Cuban, and will not be able to understand you."

"I'm going to try, anyway. Misery loves company, you know."

Harry mounted the table and put his face between the bars.

"Hist," he said.

A low moaning cry answered him.

"Bert, it's a woman," said Harry, turning in amazement to his companion, who now mounted the table beside him.

"How do you know?"

"Couldn't you hear? It was a woman's voice."

"Hist," said Harry, again, as loudly as he dared. "Who are you? Can we help you in any way?"

He hardly expected a reply for he felt, as did Bert, that they would not find any other English-speaking prisoners confined there. His surprise was great therefore, when a low voice, with just a suspicion of soft Spanish accent, asked:

"Who are you?"

"We are two American boys who would like to assist you if we can."

"Are you prisoners also?"

"We are."

"Then I fear you can be of little assistance to me, but I thank you very much for your interest. What have they shut you up for; are you friends of the insurgents?"

"We have one very good friend among them, but until we met him we did not know an insurgent from a Spanish regular. May I ask what offense you have committed against the laws of this fussy country?"

"I am a Cuban," said the soft voice, with a little gasping sob.

"Is that a crime?"

"Yes; to be a true Cuban."

"O, I see. You are what they call a sympathizer."

"Yes."

"How long have you been here?"

"I have lost count of the days and nights. I think a week."

"Have they ill-treated you?"

"Not yet, but they threaten to if I do not give them the information they seek, to-morrow."

"What do they want to know that you can tell them?"

"Much, very much, about the insurgent arms."

"And you will tell them to-morrow?"

"Not to-morrow—not ever."

The voice was low and full of tears, but there was a ring of determination that told of a strong heart despite her woman's weakness.

"Hooray," whispered Bert. "Good for you."

"And have you no friends who can aid you?"

"Yes, one, but he may even now be dead or dying in a Spanish dungeon. It is for him I weep, not for myself. There is a price upon his head."

"What," said the boys in a breath.

"Is he Captain Dynamite of the Mariella?" asked Harry, excitedly.

"He is sometimes called so. His name is Michael O'Connor. What do you know of him?"

The woman's voice trembled with excitement.

"Hoop la," whispered Harry, hardly able to refrain from shouting. "Captain Dynamite is not in any dungeon cell, Miss Juanita, and if I am not mistaken he is already devising some plan with Gomez to effect your rescue."

"Who are you," whispered the girl in amazement, "who know O'Connor and my name so well?"

"I told you, Miss Juanita, that we had one friend among the Cubans; that is Captain Dynamite. We made the last trip with him on the Mariella, though not willingly. We'll tell you that story some other time when you are well out of this."

"He was well?" nervously whispered the girl.

"Yes, until he got the dispatch from Gomez telling him that you had been captured. Then he was off to Cubitas like a shot in the middle of the night. We were trying to join him when they nabbed us."

"But they have not learned from you where he is?"

"Miss Juanita, you wrong us. We do not betray our friends."

"Oh, and it is because you will not betray him that you are here. I kiss your hands."

"Permit us to kiss yours—figuratively—Miss Juanita," said Harry, gallantly, while Bert gulped down a lump in his throat when he thought of his suggestion to tell the Spanish general the truth.

"But I wouldn't have done it, Hal, old man," he said, involuntarily.

"Wouldn't have done what?"

"Not when it came right down to bed rock."

"What are you talking about, Bert?"

"Oh, nothing. I was just thinking."

"Well, don't think so loud unless you are going to take me into your confidence. Any chance of getting out of that dungeon cell of yours, Miss Juanita?"

"None."

At this moment they heard the sound of regular footsteps outside.

"'Sh," whispered the voice. "It is the guard. Go away from the window."

The boys jumped down from the table, and as they did so, Bert stumbled and fell heavily against the wall. When he recovered his balance they heard a strange grinding sound like a heavy door creaking on rusty hinges. The boys listened in wonder.

"Gee, but this is a creepy old place," said Bert, as the noise continued. "Now, what do you suppose that is?"

"It sounds as if it came from the wall there. Let's investigate."

They moved nervously over to the stone wall that separated their prison room from that of Miss Juanita. The noise seemed nearer and more distinct, but they could see nothing that might cause it. Still the strange sound continued. In the semi-darkness they watched in wonderment the blank face of the wall from which the sound seemed to proceed. Suddenly Harry seized Bert by the arm.

"Look!" he whispered in a tense voice. He pointed to a large stone in about the centre of the wall. "Doesn't it move?"

The stone to which Harry referred was larger than any other, being three feet square, and placed about waist-high from the floor. Bert watched intently. It seemed to him that he could see a slight trembling movement and then an almost imperceptible jump as the hand of an electric clock advances with a jerk. The face of the stone, too, seemed to be out of line with the others.

They advanced closer, and Harry passed his hand cautiously under the stone. Unquestionably it had moved, either by accident or design. The upper edge projected into the room beyond the line of the wall at least an inch and the lower edge receded in the same way. As Harry's hand rested on the stone he felt it tremble and jump and the upper edge advanced another quarter of an inch into the room.

"That stone is revolving on a horizontal axis," said Harry, confidently, after his inspection. "Now the question is: How and why?"

"It seems uncomfortably like the times of the inquisition," said Bert, shuddering.

"Oh, pshaw, don't you see that wall separates us from the cell of Miss Juanita, and the Spaniards would have nothing to do with opening this passage?"

"Do you think she is doing it, then?"

"No, for had she known of the stone she would have mentioned it when I asked her if there was any chance of escape from her prison. It has come about through an accident, I feel sure, but how? Of course there must be some secret spring that works it, but where is it and how and by whom has it been operated?"

"Hal, I believe I did it," whispered Bert, excitedly.

"What on earth do you mean?"

"You know when I jumped down from the table I fell against the wall. It was immediately after that we heard the creaking."

"Thunder, you are right. You must have touched the spring."

"I think so. Let's look for it."

The boys carefully examined the wall near the place where Bert had stumbled, and to the left of the revolving stone they found a small, diamond-shaped stone that to the casual observer would appear to have been set in the wall to fill in the broken corner of one of the larger stones. Upon close inspection they found that it was set loosely in the wall without mortar. They dared not touch it for fear it might stop the invisible machinery that it had evidently set in motion.

Slowly the stone continued its unsteady revolution, until at the end of about five minutes the creaking stopped, there was a clicking sound as if a cog had settled into place, and all movement ceased. The big slab, which was six inches thick, had now obtained a horizontal position, leaving an opening above and below into the next room, or cell. The axis upon which the stone revolved was a little above the centre, so that the lower opening was nearly eighteen inches high.

The boys peered through into the darkness of the next cell.

"Miss Juanita," called Harry, softly. "May we come in? Perhaps this scheme of opening walls may continue through to the outside world."