"Peabody," whispered Everett. "Call him," commanded Monica. "The others might hear," objected Everett. "We must overtake him. If we're with him when they meet, they wouldn't dare--" With a gasp of astonishment, his words ceased. Like a ghost, the ghostlike figure had vanished. "He walked through that rock!" cried Monica. Everett caught her by the wrist. "Come!" he commanded. Over the face of the rock, into which Peabody had dived as into water, hung a curtain of vines. Everett tore it apart. Concealed by the vines was the narrow mouth to a tunnel; and from it they heard, rapidly lessening in the distance, the patter of footsteps. "Will you wait," demanded Everett, "or come with me?" With a shudder of distaste, Monica answered by seizing his hand. With his free arm Everett swept aside the vines, and, Monica following, they entered the tunnel. It was a passageway cleanly cut through the solid rock and sufficiently wide to permit of their moving freely. At the farther end, at a distance of a hundred yards, it opened into a great vault, also hollowed from the rock and, as they saw to their surprise, brilliantly lighted. For an instant, in black silhouette, the figure of Peabody blocked the entrance to this vault, and then, turning to the right, again vanished. Monica felt an untimely desire to laugh. Now that they were on the track of Peabody she no longer feared the outcome of the adventure. In the presence of the American minister and of herself there would be no violence; and as they trailed the archaeologist through the tunnel she was reminded of Alice and her pursuit of the white rabbit. This thought, and her sense of relief that the danger was over, caused her to laugh aloud. They had gained the farther end of the tunnel and the entrance to the vault, when at once her amusement turned to wonder. For the vault showed every evidence of use and of recent occupation. In brackets, and burning brightly, were lamps of modern make; on the stone floor stood a canvas cot, saddle-bags, camp-chairs, and in the centre of the vault a collapsible table. On this were bottles filled with chemicals, trays, and presses such as are used in developing photographs, and apparently hung there to dry, swinging from strings, the proofs of many negatives. Loyal to her brother, Monica exclaimed indignantly. At the proofs she pointed an accusing finger. "Look!" she whispered. "This is Peabody's darkroom, where he develops the flash-lights he takes of the hieroglyphs! Chester has a right to be furious!" Impulsively she would have pushed past Everett; but with an exclamation he sprang in front of her. "No!" he commanded, "come away!" He had fallen into a sudden panic. His tone spoke of some catastrophe, imminent and overwhelming. Monica followed the direction of his eyes. They were staring in fear at the proofs. The girl leaned forward; and now saw them clearly. Each was a United States Treasury note for five hundred dollars.