Their prow was pointed to the south, save where the windings of the river caused a temporary change of their course. The shores on either side were low, and generally flat, with here and there clumps of trees and little patches of grass. They were still in the region of the desert, but it was not altogether barren, like the great Atmoor of Korosko. Flocks of ducks and geese flew in the air or settled in the nooks along the shore; and now and then the ibis, the sacred bird of the Egyptians, showed his tall form on the sand-banks. Occasionally a crocodile lay basking in the sun, or the snort of a startled hippopotamus would be heard close to the boat. In the night the clear sky was studded with stars, and the youths lingered long on deck, studying the various constellations. The north star was nearly sunk to the horizon behind them, while in front the Southern Cross sparkled in all its glory, and recalled memories of their voyage from Singapore into the Java Sea. Once more they were approaching the equator, but with far greater difficulties before them. The steamboat held her course during the night, and in the morning our friends opened their eyes on a change of scene. [Illustration: A VILLAGE SCENE.] The monotonous plain had been left behind, and they were in a region of hills. More than this, the region was no longer a desert. The hills were studded with trees, and on the banks of the river there was a succession of forests and cultivated fields, quite unlike the picture presented below Khartoum. Droves of cattle and flocks of sheep and goats were numerous, and the conical huts of the natives had no resemblance to the flat-roofed dwellings of Lower Egypt. Occasionally a train of camels was visible, wending its stately way along, and making a sharp contrast to the droves of diminutive donkeys peculiar to this part of the Nile. Where the boat went close to the banks the boys several times discovered monkeys playing among the branches of the trees, and Frank would have made no objection if they had halted long enough to capture one of the amusing beasts. A mountain-range appeared in the distance; the vegetation steadily increased in luxuriance; and the boys became fully aware that they were nearing THE HEART OF AFRICA. [Illustration: THE HEART OF AFRICA.] CHAPTER VI. AMONG THE SHILLOOK NEGROES.--ARRIVAL AT FASHODA.--EXPLORERS OF THE NILE. On the second day from Khartoum, Doctor Bronson told the boys they were in the country of the Shillooks. The natural inquiry that followed this announcement was, "Who are the Shillooks?"