Grasping his pistol tightly in his right hand, and steadying himself with his left, Reeves turned in his saddle and took a swift yet comprehensive view of the pursuing Arabs. There were five of them, all fully clad in white, showing that they were the chief men of the tribe. Each had a gun slung across his shoulder, and by the length of the barrels the Englishman knew, to his satisfaction, that they were smooth-bore flintlocks, and not the modern rifles used by the Arabs on the coast. Gun flints are practically indestructible, and gunpowder can be manufactured by the Arabs under the most rough-and-ready conditions; but cartridges are comparatively scarce. Consequently, for all ordinary purposes--except in inter-tribal fights, when rapid firing is essential to success--the denizens of the desert prefer to husband their supplies of modern ammunition, and prefer to use flint. "They are gaining slightly, I fear," remarked Reeves. "Still, we have a fighting chance. I wish we could take aim." On they tore, pursuers and pursued, till at length one of the Arabs took a flying shot. The bullet fell short, knocking up a shower of sand barely forty yards behind the Englishmen. This was a certain sign that the intervening distance was diminishing. "What's that ahead?" exclaimed Gerald, pointing to a small, black, pillar-like object in the sand a full mile away. "It's a rock," replied Hugh. "That's a blessing!" ejaculated Reeves, for his camel was beginning to show signs of having over-exerted himself. "I only hope there are no more of the brutes in ambush," he muttered. There were two alternatives--either halting and making a stand in the open, or taking the risks that the rock already concealed more of the Arabs, and, if not, enjoying the advantages of fighting with their backs against a wall. Reeves chose the latter. It was evident that flight was now out of the question, for, in addition to his hierie showing signs of fatigue, the lads' camels were almost at the end of their stride. At length the fugitives drew up at the place they had selected, to make their desperate defence. It was, on closer acquaintance, a large mass of rock, sheer on three sides, and sloping steeply on the remaining front. The most active climber in the world could not hope, without climbing implements, to scale the perpendicular sides, which were quite twenty feet in height, and worn smooth by the action of sandstorms through countless ages. At the base of the fourth side there was a fairly wide trench, partly filled with drifting sand, a low wall of irregularly-shaped rock forming a breastwork about two feet in height. "Couldn't be better!" exclaimed Reeves, as he slipped from his camel. "Be sharp; make these brutes lie down. Never mind that; it's over." This last remark was addressed to Gerald, who ducked his head as a bullet flattened itself out upon the rock a good six feet from the ground.