They proceeded warily. On gaining the opposing height they found that a broad plateau, flanked by a steep hill on the seaward side, barred any distant view, but Abdur Kad'r felt assured that the crest of this next hill would give them command of the whole range of broken country for many miles ahead. With this objective, they urged the camels into a trot. When the shoulder of the rising ground became almost impassable for four-footed animals, and awkward beasts at that, they dismounted, tied the camels to heavy stones, and climbed the remainder of the way on foot. They looked across a narrow valley into a wide and shallow depression, where a clump of palm trees and dense patches of _sayall_ bushes instantly revealed the whereabouts of the oasis. It was easy to see the regular lines of newly-turned rubble and sand where trenches had been cut by the explorers. But the place was deserted. Not a man or horse, camel or tent, stood on the spot where the mirage had revealed a multitude some twenty-six hours earlier. Royson was so perplexed by the discovery that his gaze did not wander from the abandoned camp. Abdur Kad'r, quicker than he to read the tokens of the desert, pointed to a haze of dust that hung in the still air far to the north. "The Italians have gone, Effendi," he said. "Perhaps they, too, were looking for an oasis with five hills. Behold, they have found one by a fool's counting, for this is the fifth hill within two kilometers of Suleiman's Well. The ways of Allah are wonderful. Can it be that they have discovered that which you seek?" A sharp pang of disappointment shot through Royson's breast. He was about to tell Abdur Kad'r that they must now regain their camels and hasten to the oasis while there was sufficient light to examine the excavations, when the sheikh suddenly pulled him down, for Dick had stood upright on a boulder to obtain an uninterrupted field of vision. "Look!" he growled. "Four of them! And, by the Holy Kaaba, they mean mischief!" Royson's eyes were good, clearer, in all probability, than the Arab's, but they were not trained to detect moving objects with such minute precision. Nevertheless, in a few seconds he made out the hoods of four men who were peering over the crest which separated the small valley from the larger one. They disappeared, and, while Royson and Abdur Kad'r were speculating on the motive that inspired this espionage, the hoods came in sight again, but this time they had the regular swing that betokened camel-riders. The four halted on the sky-line, and seemingly exchanged signals with others in the fear. Then they resumed their advance. They were fully armed; they carried their guns across the saddle-bow, and Dick saw that their cloaks were rather differently fashioned to those which he had taken note of hitherto. "Hadendowas!" murmured Abdur Kad'r. "They are good fighters, Effendi, but born thieves. And how many ride behind? Not for twenty years have I met Hadendowas on this track."