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."