The position of the moon had cast the greater part of the _wâdi_ into deep shadow. There was a gap in the irregular wall nearly opposite to Barry’s tent through which a certain amount of light came, but right and left of it lay ebony darkness. As he came out and joined Professor Blackwell: “There’s a party of Arabs up on the caravan road!” said the latter in a low, urgent voice. “Where is my father?” Barry whispered. “Here I am, Barry!” came a reply out of the darkness. “Speak softly. Voices carry for miles in this place.” Barry groped his way in the direction of the speaker. “Is Danbazzar here?” he asked. “I’m right here!” Danbazzar answered in a harsh whisper; then, speaking more softly: “Who fired that shot?” he demanded. “I don’t know,” Professor Blackwell returned. “It came from high up in the mountains. It must have been one of the Arabs.” “I wonder!” murmured John Cumberland. “I make the time half after two. The second shift comes on at four. So that no one is likely to have been moving--unless one of the watchmen may have seen something.” “_Sssh-ssh!_” came a warning. “Look!” High on the ridge above them, like some spirited ebony statue, the figure of a horseman appeared, a magnificent silhouette against the deepening blue of the sky! A moment he remained there. Then--no sound reaching their ears--he disappeared magically, as he had come! “I want someone to go up to the excavation.” It was Danbazzar speaking in a suppressed undertone. “Shall _I_ go and leave you in charge, Mr. Cumberland, or----” “I’ll go!” Barry volunteered promptly. “You may be wanted here.” “It’s just possible,” Danbazzar went on, “that something may have gone wrong there. It is also possible they mayn’t know the Arabs are here. Order everybody to stay under cover except the guards. All work to be suspended till further instructions. Got it clear?” “All set,” Barry replied promptly. “Be careful, my boy,” said John Cumberland; “and don’t forget the signal, or our own men may attack you, if they are on the _qui vive_.” A big muscular hand grasped his. “Here,” said Danbazzar, “take this.” He found a service revolver thrust into his fingers. Thereupon he set off, rejoicing in the adventure yet wishing that Jim Sakers could have been there to share it with him. He moved with great caution. In this desert stillness, the slightest sound was audible for miles.… At some points in the journey, the _wâdi_ left behind, that ridge along which the caravan road ran was visible; at other points it became lost to view. But always Barry slunk in the shadows, sometimes dropping prone and wriggling for several yards, in order that he might take advantage of some narrow belt of shadow; ever conscious, when the dangerous ridge was in sight, of the possibility of being seen, or worse--of being shot.