They now entered a succession of marshes and low ground, where the river frequently divided into several channels, and was often partially blocked with great masses of weeds and other tropical vegetation. A short distance above the Sobat, Frank and Fred had their first view of a wild elephant, or rather of a troop of half a dozen or more. They were not at all disturbed by the proximity of the steamer. One was lying comfortably on the ground, and the rest stood watching the boat while it passed up the stream a few hundred yards from them. On the opposite bank of the river was a Shillook village, and beyond it the dry grass was burning furiously and sending up a vast column of smoke. The boys were much excited over their view of the elephants, and greatly wished they could land and take a shot at the beasts. Doctor Bronson told them they would have an opportunity to hunt elephants before many days, and with this assurance they were contented. Elephants roam the country on both banks of this part of the Nile, but they are less numerous than farther up the valley. They are hunted for their ivory by the natives, and occasionally the white man gets a chance at them. Every year they increase in scarcity and in shyness, so that the stranger's chance of sport among this huge game is not very good. Occasionally they visit the fields of the natives during the night, and do a great deal of damage by trampling down the crops and eating the growing plants. The negroes take advantage of their depredations to make pitfalls for them, and in this way a large elephant sometimes finds himself a prey to the hunter. As they ascended the Nile above the mouth of the Sobat, Abdul pointed out the spot where the "sudd" formerly obstructed the river, and caused great inconvenience. The sudd had been mentioned before, but only briefly, and one of the youths asked Abdul to describe it to them. "From here to Gondokoro," said Abdul, "a distance of nearly eight hundred miles, you will find the White Nile running through a series of marshes and lowlands; in many places it spreads out over a wide area, and forms a large number of channels among islands of greater or less extent. You have already observed that the grass and reeds come drifting with the current, and occasionally masses of them form to such an extent that they take the shape of floating islands. "This floating stuff sometimes becomes caught and imprisoned at low water, and it remains there, growing day by day, till the annual flood brings down so large a current that it is swept away. One year the flood was not sufficient to remove it, and it remained from one season till the next.