He began measuring. First he located the line across the floorjoists overhead, where rested the partition separating the dining-room from the parlour. Finding the middle of this line, he dropped an improvised plumb-line to the ground; and from this spot as centre, using a string about ten feet long, he described a circle on the earth. Then, referring to his calculations, he proceeded to locate several points with small stakes pressed into the soil. Then he checked them off and nodded.

“It's even better than the professor thought. His theory is all but proven. If Jerome and Hume can deliver the other stone without accident, we can save those now inside the Spot.” Then, very solemnly: “But we face a heavy task. It will be another Thermopylae. We must hold the gate against an occult Xerxes, together with all his horde.”

“The hosts of the dead!” exclaimed Mme. Le Fabre.

“No; the living! Just give me time, Madame, and you will see something hitherto undreamed of. As for your theory—tomorrow you may doubt whether you are living or dead! In other words, Dr. Holcomb has certainly proved the occult by material means. He has done it with a vengeance. In so doing he has left us in doubt as to ourselves; and unless he discovers the missing factor within the next few hours we are going to be in the anomalous position of knowing plenty about the next world, but nothing about ourselves.”

He paused. He must have known that their curiosity could not hold out much longer. He said:

“Now, just one thing more, friends, and I can tell you everything, while we are waiting for Jerome and the general to return. But first I must see the one who preceded me out of the spot.”

“Ariadne!” from Charlotte, in wonder.

“Ariadne!” exclaimed Watson. He was both puzzled and amazed. “Did you call her—Ariadne?”

“She is upstairs,” cut in Dr. Higgins.

“I must see her!”