The expressions of anger hitherto portrayed on the countenances of the Arabs had given place to those of anxiety. They knew that an enemy was hovering around them, an enemy whom they had wronged, whose power they had undervalued, and whom they had foolishly restored to liberty. The bodies of their companions were hastily interred in the sand, and their journey northward was once more resumed. CHAPTER FIFTY SEVEN. A CALL FOR TWO MORE. The sufferings of slaves for water and food again commenced, while the pace at which they were compelled to travel, to keep up with the camels, soon exhausted the little strength they had acquired from the rest by the well. During the long afternoon following the burial of the two Arabs, each of the boy slaves at different times declared his utter inability to proceed any further. They were mistaken; and had yet to learn something of the power which love of life exerts over the body. They knew that to linger behind would be death. They did not desire to die, and therefore struggled on. Like men upon a treadmill, they were compelled to keep on moving, although neither able nor willing. The hour of sunset found them wading through sand that had lately been stirred by a storm. It was nearly as light and loose as snow; and the toil of moving through it was so wearisome that the mounted Arabs, having some pity on those who had walked, halted early for the night. Two men were appointed to guard the camp in the same manner as upon the night before; and with the feelings of hunger and thirst partly appeased, weary with toils of day, our adventurers were soon in a sound slumber. Around them, and half buried in the soft sand, lay stretched the other denizens of the _douar_, all slumbering likewise. Their rest remained undisturbed until that darkest hour of the night, just before the dawning of day. They were then startled from sleep by the report of a musket, a report that was immediately followed by another in the opposite direction. The _douar_ was instantly in wild confusion. The Arabs seized their weapons, and rushed forth from among the tents. One of the party that ran in the direction in which the first shot was heard, seeing a man coming towards them, in the excitement of the moment fired his musket and shot the individual who was advancing, who proved to be one of those entrusted with the guard of the camp. No enemies could be discovered. They had fled, leaving the two camp guards in the agonies of death. Some of the Arabs would have rushed wildly hither and thither in search of the unseen foe, but were prevented by the sheik, who, fearing that all would be lost, should the _douar_ be deserted by the armed men, shouted the signal for all his followers to gather around him.