At the end of the next march, which was made by day, the guides, whose memories had been refreshed by flogging, discovered a large pool of good water, and all drank deeply in thankful joy. A small but strong zeriba was built near this precious pool, and the reserve food and a few sick men were left with a small garrison under an Egyptian officer. The column resumed their journey. On the 29th they reached Aigaila, and here, with feelings of astonishment scarcely less than Robinson Crusoe experienced at seeing the footprint in the sand, they came upon the Khalifa's abandoned camp. A wide space had been cleared of bush, and the trees, stripped of their smaller branches, presented an uncanny appearance. Beyond stood the encampment--a great multitude of yellow spear-grass dwellings, perfectly clean, neatly arranged in streets and squares, and stretching for miles. The aspect of this strange deserted town, rising, silent as a cemetery, out of the awful scrub, chilled everyone who saw it. Its size might indeed concern their leader. At the very lowest computation it had contained 20,000 people. How many of these were fighting men? Certainly not fewer than 8,000 or 9,000. Yet the expedition had been sent on the assumption that there were scarcely 1,000 warriors with the Khalifa! Observing every precaution of war, the column crawled forward, and the cavalry and Camel Corps, who covered the advance, soon came in contact with the enemy's scouts. Shots were exchanged and the Arabs retreated. The column halted three miles to the east of this position, and, forming a strong zeriba, passed the night in expectation of an attack. Nothing, however, happened, and at dawn Mitford was sent out with some mounted 'friendlies' to reconnoitre. At ten o'clock he returned, and his report confirmed the conclusions which had been drawn from the size of the Aigaila camp. Creeping forward to a good point of view, the officer had seen the Dervish flags lining the crest of the hill. From their number, the breadth of front covered, and the numerous figures of men moving about them, he estimated not fewer than 2,000 Arab riflemen in the front line. How many more were in reserve it was impossible to say. The position was, moreover, of great strength, being surrounded by deep ravines and pools of water.