The river below Khartoum flows steadily along till it reaches the 6th or Shabluka cataract (_see_ p. 47). Below this it is not disturbed, except for the rapids of the so-called 5th or El Homar and Bagara cataracts, till it passes Abu Hamed and enters the 4th or Belal cataract some way below this point. This cataract, forming the most complicated and dangerous rapids on the Nile, is for ordinary purposes unnavigable (_see_ p. 36). Below it there is an open stretch past Dongola to the 3rd or Hannek cataract, shortly followed by the Kajbar rapids (_see_ p. 26). A rocky channel full of small islands and small rapids, increasing in size and importance as the river proceeds, is entered some 80 miles below Kajbar, and through the Batn El Hagar the river rumbles along till, after passing the 2nd or Amka cataract, it emerges past Halfa in a broad and steady stream which lasts till it arrives at the dam and 1st cataract (Shellal) of Aswan. From here onwards there are no further obstacles (except sand-banks and canals) till, _viâ_ the Delta of Egypt, the Mediterranean Sea is gained. (iii.)—RIVER DISCHARGES. The following, taken from Sir W. Garstin’s Report above mentioned, gives a summary of results respecting discharges in the basin of the Upper Nile:— 1. THE VICTORIA NILE. The discharge at the Ripon Falls varies between 500 and 650 metres cube per second with a range of 1·1 metres. Downstream of the Murchison Falls the range is probably 1 metre, and the maximum and minimum discharges 1,000 and 400 metres cube per second respectively. The increase in flood is due to the rainfall throughout the catchment area of the river between these two points, while the decrease during the low season is due to the Choga Lake, which undoubtedly has a regulating effect upon the supply issuing from Lake Victoria. Lastly, the volume which enters Lake Albert by this river is generally, in flood, greater than that which leaves it by the Bahr El Jebel. 2. THE BAHR EL JEBEL. At Wadelai, the first discharge site, the range of the river is about 1·11 metres while the discharge varies from 550 to 950 metres cube per second. The increase brought in by the streams which feed this river between Lake Albert and Wadelai is compensated by the loss of water due to a portion of the discharge of the Victoria Nile passing south up the lake during the flood season.