Moya, bringing up the rear, could hear Bleyer explain the workings to those at his heel. He talked of stopes, drifts, tunnels, wage scales, shifts, high-grade ore, and other subjects that were as Greek to Joyce and India. The atmosphere was oppressively close and warm, and the oilskins that Moya wore seemed to weigh heavily upon her. She became aware with some annoyance at herself that a faintness was stealing over her brain and a mistiness over her eyes. To steady herself she stopped, catching at the rough wall for support. The others, unaware that she was not following, moved on. With a half articulate little cry she sank to the ground.

When she came to herself the lights had disappeared. She was alone in the most profound darkness she had ever known. It seemed to press upon her so ponderably as almost to be tangible. The girl was frightened. Her imagination began to conjure all sorts of dangers. Of cave-ins and explosions she had heard and read a good deal. Anything was possible in this thousand-foot deep grave. In a frightened, ineffective little voice she cried out to her friends.

Instantly there came an answer--a faint tapping on the wall almost at her ear. She listened breathlessly, and caught again that faint far tap--tap--tap--tap--tap--tap--tap. Instinctively her hand went out, groping along the wall until it fell upon a pipe. Even as she touched this the sound came again, and along with it the faintest of vibrations.

She knew that somebody at a distance was. .h.i.tting the pipe with a piece of quartz or metal.

Stooping, she found a bit of broken rock. Three times she tapped the pipe. An answer came at once.

Tap--tap--tap--tap--tap--tap--tap!

She tried two knocks. Again the response of seven taps sounded. Four blows brought still seven. Why always seven? She did not know, but she was greatly comforted to know that her friends were in communication with her. After all she was not alone.

A light glimmered at the end of the tunnel and moved slowly toward her.

Bleyer's voice called her name. Presently the whole party was about her with sympathetic questions and explanations.

She made light of her fainting attack, but Verinder insisted on getting her back to the upper air in spite of her protests. He had discovered that Joyce was quite ready to return to the sunlight, now that her curiosity was satisfied. A very little of anything that was unpleasant went a long way with Miss Seldon, and there was something about this underground tomb that reminded her strongly of an immense grave.

At dinner Verinder referred to the attack of vertigo. "Feel quite fit again, Miss Dwight?"

"Quite, thank you." Moya was a little irritated at the reference, because she was ashamed of having given way to physical weakness. "It was nothing. I was a goose. That's all."

Bleyer, a guest for the evening, defended the young woman from her own scorn. "It often takes people that way the first time, what with the heat and the closeness. I once knew a champion pugilist to keel over while he was going through a mine."

"Were you afraid when you found yourself alone?" Joyce asked.

"I was until you tapped."

India looked puzzled. "Tapped. What do you mean?"

"On the pipe."

"What pipe?"

"The one that ran through the tunnel."

Miss Kilmeny shook her head. "I didn't see anybody tap. Perhaps one of us touched it by chance."

"No. That couldn't be. The tap came seven times together, and after I had answered it seven times more."

"Seven times?" asked Bleyer quickly.

"Yes--seven. But, if you didn't tap, who did?"

"Sure it wasn't imagination?" Verinder suggested.

"Imagination! I tell you it was repeated again and again," Moya said impatiently.

"Spirit rapping," surmised Joyce lightly. "It doesn't matter, anyhow, since it served its work of comforting Moya."

"It might have been some of the workmen," Lady Farquhar guessed.

"Must have been," agreed Bleyer. "And yet--we're not working that end of the mine now. The men had no business there. Odd that it was seven raps.

That is a call for help. It means danger."

A bell of warning began to toll in Moya's heart. It rang as yet no clear message to her brain, but the premonition of something sinister and deadly sent a sinking sensation through her.

Verinder sat up with renewed interest. "I say, you know--spirit rapping.

Weren't you telling me, Bleyer, that there was a big accident there some years ago? Perhaps the ghosts of some of the lost miners were sending a message to their wives. Eh, what?"

"The accident was in the Golden Nugget, an adjoining mine. The property was pretty well worked out and has never been opened since the disaster."

The color had ebbed from Moya's lips. She was a sane young woman not given to nerves. But she had worried a great deal over the disappearance of Jack Kilmeny. This, coming on top of it, shook her composure. For she was fighting with the dread that the spirit of the man she loved had been trying to talk with her.

Joyce chattered gayly. "How weird! Moya, you must write an account of your experience for the Society for Psychical Research. Put me in it, please."

"Of course, it must have been some of the men, but I don't see----"

Moya interrupted the superintendent sharply. An intuition, like a flash of light, had illumined her brain. "Where does that pipe run, Mr.

Bleyer?"

"Don't know. Maps of the workings at the office would show."

"Will you please find out?"

"Glad to look it up for you, Miss Dwight. I'm a little curious myself."

"I mean now--at once."

He glanced at her in quick surprise. Was she asking him to leave the dinner table to do it? Lady Farquhar saw how colorless Moya was and came to the rescue.

"My dear, you are a little unstrung, aren't you?" she said gently. "I think we might find something more cheerful to talk about. We always have the weather."

Moya rose, trembling. "No. I know now who called for help. It was Jack Kilmeny."

Verinder was the first to break the strained silence. "But that's nonsense, you know."

"It's the truth. He was calling for help."

"Where from? What would he be doing down in a mine?"

"I don't know.... Yes, I do, too," Moya corrected herself, voice breaking under the stress of her emotion. "He has been put down there to die."

"To die." Joyce echoed the words in a frightened whisper.

Dobyans laughed. "This is absurd. Who under heaven would put him there?"

A second flash of light burned in upon the girl. "That man, Peale--and the other ruffian. They knew about the shipment just as you did. They waylaid him ... and buried him in some old mine." Moya faced them tensely, a slim wraith of a girl with dark eyes that blazed. She had forgotten all about conventions, all about what they would think of her.

The one thing she saw was Jack Kilmeny in peril, calling for help.