If we take 3,000 cubic metres per second as the average annual flow past Assuân we may say that the White Nile supplies 24% off more than half the area of the whole basin, the Blue Nile 65% off ¹⁄₁₀ the area, and the Atbara 11% off ¹⁄₁₂ the area. The Gazelle river drains about ¹⁄₆ the total area and adds practically 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 I. 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 paragraph, 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 to fail. The catchment basin of the Gazelle river may be credited with a mean annual rainfall of 75 centimetres between May and October, while the mean annual rainfall on the Arab river cannot be more than 30 centimetres between June and September. The Sobat river in its upper reaches enjoys an annual rainfall of about 1.25 metres and of ·75 metres in its lower reaches. The time of rain is between March and September. The lands draining into the White Nile north of Tewfikieh have an annual rainfall of about 20 centimetres between June and September.