It was a strange experience to sit outside the tent door that night, breathing the soft moist air which seemed so different from the dry, harsh, parching wind of the desert. There was the pleasant scent of growing plants, too, rising from wherever the overflow from the fountains permeated the sand, quite unseen in the broad sunshine, but showing its effect in a blush of green which gradually grew less and less, till at a few hundred yards from the rocks and pools it died right away and all was arid barrenness once more. Now and then a wailing howl came from a distance, to be answered here and there by the prowling animals which scented the food of the camp, and hung about waiting till the caravans had passed on to make a rush in safety for the scraps that were left, with the result that the neighbourhood of the pools and wells was found free from all refuse by the next comers. The Hakim's party was too weary with the nervous excitement and hard labour of the past day to talk much, finding it pleasanter to sit or recline and listen to the various sounds that reached their ears from the Baggara camp or far out in the desert, till after being absent for some little time the Sheikh came softly up to the tent and waited to be questioned. He did not have to wait long, for the professor attacked him at once. "Well, Ibrahim," he said, "what news?" "Little, Excellency. The Baggara have sentries out all round the camp." "And ours?" "Yes, Excellency; we are prisoners." "But in no danger?" "No, Excellency. It is peace between us and the fighting men. But if they are attacked in the night or just before daybreak we are in bad company, as you would say, and we shall perish with these tribesmen if they are beaten." "That sounds bad," said the professor. "But look here, who is likely to attack their camp?" "Who can say, Excellency? Like the people of old, their hand is against every man, and every man's hand is against them. They are wandering about harassing villages, plundering, and making slaves. Some of the village people may take heart and join together to slay them; or the Khedive's men may hear of their being in the neighbourhood, and come from boats upon the river. There may be soldiers of your own journeying south, who, hearing from spies that a party of the Khalifa's men have come so far north, would be sure to try and scatter them like the sand before the storm." "But, on the other hand," said the doctor quietly, "none of these things may happen, and we may sleep in peace and trust that all will be well." "Yes, Excellency; that is what we must do always." "Then let us sleep while we can," said the doctor. "I am very weary, and there is sure to be plenty more hard work to-morrow."