194 PEOP. E. HULL, LL.D., P.E.S., ON THE PEOPOSED SCHEME 



impetuous torrent. Descending towards the plains, the 

 waters break down the high banks of alluvial mud, churning 

 it into fine silt, and thus held in suspension, the sohd matter 

 is carried onwards towards the main stream of the White 

 Nile, two hundred miles below Khartoum; and, impregnating 

 the whole body of the river, passes onwards towards Lower 

 Egypt and the Mediterranean, scattering fertility on either 

 hand along its course. The White Nile rising in the 

 Victoria Nyanza, although augmented by tributaries which 

 descend from the highlands beyond Darfur as well as the 

 tributaries of the Albert Nyanza,* and other streams such 

 as the Bahr-el-Azrak (or Blue Nile), contributes but little 

 to the sediment which is so essential to the fertility of the 

 Nile valley. The Atbara appears to be the most important 

 source of this fertilising mud ; and it is only by a visit to the 

 valley of the Nile, that the traveller becomes impressed Avith 

 the idea how essential are these annual floods of muddy 

 water, utilised by means of the net-work of irrigating 

 channels, to the fertility of the Nile valley and the great 

 plain of Lower Egypt.f Should this process be interrupted 

 only for a very few years these fruitful terraces and plains 

 would be converted into the condition of the arid sandy 

 deserts which border them on either hand. 



In order to approach our subject it is necessary to recollect 

 that under the existing natural system of "High" and 

 •" Low " Nile, Egypt is subjected to winter irrigation, which 

 reaches its maximum height during the months of September 

 and October, Early in June the river, which had fallen to 

 its lowest level in March and April and for some weeks 

 onwards, begins to rise ; and this rise progresses somewhat 

 rapidly during the months of July and August, reaching its 

 maximum about the begimiing of October as stated above, 

 when the reverse process sets in, and after two or three 

 periods of oscillation, the waters begin to fall during 

 November and the following months. As the season of 

 harvesting after the period of "High Nile" begins in 

 December, it would be manifestly of enormous advantage if, 

 with the high temperature which prevails all the year round, 



* Which Baker claims as the source of the Nile, but being a smaller 

 lake than the Victoria must give way. 



+ On the subject of irrigation of Egypt see Three Lectures by Sir 

 Colin Scott-Monci'ieff, Professional Papers of the Corps of Royal Engineers, 

 vol. xix (1893). 



