“Where’s Bob?” called Frank, in an anxious tone. He and the big fellow were very close. Frank’s mother had died when he was a baby, and his father, business partner of Bob Temple’s father, had followed her a few years later. Ever since, the orphaned Frank had made his home with the Temples, and he was engaged to Bob’s sister, Della. To Frank’s anxious inquiry, Mr. Hampton added: “When Ali’s camel came in alone we knew something had happened and set out to meet you at once.” “Well, Dad, something has happened all right,” said Jack, dejectedly. “Or rather it’s all wrong. Bob has been captured. We don’t know how.” Thereupon, while they all made their way back to the oasis, he proceeded to explain events as they had occurred so far as he knew them. What actually had happened in Bob’s case, of course, was not known. But as our readers know, Jack and Ali had guessed at the truth. By the time the account was concluded, they had arrived at the encampment and dismounted. Mr. Hampton looked very grave and care-worn. The deaths of the Professor and Ben Hassim already had weighted him down. Now the capture of Bob, whom he loved as if he were a son, filled him with grief. A malignant, unseen power seemed pursuing this expedition, which had started out peacefully intent only on establishing amicable relations with the mysterious dwellers of the Shaitun Mountains and on adding to the sum of the world’s useful knowledge. Truly, he thought, gazing out through the trees of the oasis across the vast reaches of the desert toward the mountains on the far northern horizon, truly, they were well named the mountains of Satan. Had he had any premonition of the reception with which they would meet at the hands of the Athensians, Mr. Hampton never would have financed nor launched the expedition. But he realized the futility of vain regrets. Now was not the time to devote to such thoughts. One thing must be done, one thing alone, and done at once; that was, to start swift pursuit for the purpose of rescuing Bob. Turning to the boys, he bade them pack up at once the few things absolutely necessary, but not to incommode themselves with articles which could be dispensed with. As they leaped to obey, he ordered Ali to summon the Arabs. The men who already had received from Ali a brief account of what had occurred on the ostrich hunt, quickly assembled. Their swarthy determined faces formed a group at which Mr. Hampton looked with approval. Picked men all, he could not ask for better support at his back. Nevertheless, he felt it was only fair that they should be appraised fully of the dangers attendant upon the proposed expedition, and should be allowed to exercise their own choice as to whether to accompany him or not.