18 — 
the highlands of Central Africa. The general level of the area may 
be taken as 1400 metres above sea level. 
The area draining into Lake Victoria is 240,000 square kilometres. 
At the outlet of Lake Albert this has increased to 380,000, and at 
Gondokoro to 470,000. The Gazelle river drains 470,000 square 
kilometres, and the Sobat 160,000. The White Nile drains altogether 
1.690.000 square kilometres, or more than half the total area of the 
catchment basin of the Nile. The Blue Nile drains 300,000 square 
kilometres and the Atbara 240,000. The Nile below the Atbara 
junction is draining 2,290,000 square kilometres. Between the Atbara 
mouth and the sea, the Nile drains whatever falls on a desert area of 
720.000 square kilometres. 
If we take 3,000 cubic metres per second as the average annual flow 
past Assuan we may say that the White Nile supplies 24 °/ 0 off more 
than half the area of the whole basin, the Blue Nile 65 °/ 0 off ^ the 
area, and the Atbara 11 °/ 0 off ^ the area. The Gazelle river drains 
about ^ the total area and adds pratically nothing to the discharge. 
Table 24 should be very carefully studied by any man who wants to 
understand the Nile. It does not pretend to exactitude, but embodies 
the best information I have been able to obtain. 
6. — The climate of the Nile valley.— This paragraph would 
have been much more complete if Capt. Lyons’ monograph on the 
Meteorology of the Nile valley had been published. In considering the 
climate I shall follow the subdivisions of the catchment basin of the 
Nile contained in Table 1. 
In the catchment basins of Lakes Victoria and Albert, the mean 
annual rainfall may be taken as 1.25 metres, with great fluctuations 
between good and bad years. Neglecting here and through this para- 
graph, the light occasional falls of rain which are trying to travellers 
but which have no effect on the rivers, it may be said that in these 
basins there are two rainy seasons, the greater in March, April and 
May, and the lesser in October, November and December. The former 
are followed by dry southern winds, while north winds blow in the 
winter. 
Along the whole of the Albert Nile, the mean annual rainfall may 
be taken as 1 metre, with severe famines in occasional years and 
heavy rainfall in others* The principal rains are between May and 
November, with the maximum between August 15 and September 15* 
In years of deficient rainfall, the June, July and August rains seem 
