FOE EMBANKING THE WATERS OF THE NILE. 199 



1. Gain to the State £850,000 per annum. 



2. Increased value of the crops from Upper, Middle, and 



Lower Egypt £16.000,000 per annum. 



The above estimates are sufficiently remarkable, but may be 

 accepted as resting on the authority of officials well ac- 

 quainted with the conditions and requirements of the country. 

 We have now to consider the mode by which the pereunial 

 irrigation is to be carried out. 



The massive dam to be thrown across the river below 

 Philge is to be furnished with a large number of undersluices 

 at short distances, and of sufficient size to allow the entire 

 summer flood to pass freely as at present, and to carry off 

 the sediment with which the waters are at that period so 

 largely charged. This arrangement will prevent the deposi- 

 tion of the sediment over the bed of the reservoir and its 

 ultimate silting up, as has been too often the case with 

 reservoirs in India and elsewhere. After the flood waters 

 have subsided towards the end of October, the regulating 

 gates will be closed, and so remain during the three following 

 months ; and as the waters at this period are mainly drawn 

 from their Central African sources and contain but little 

 sediment, no silting is anticipated. By the end of this 

 period they will have risen to their flood-level, and will be 

 available for the second process of irrigation by means of 

 the great lateral canals which will be carried down on both 

 sides of the valley. There will, however, be a slight diff'er- 

 ence in the periods during which the water will be drawn 

 from the reservoir for Upper and Middle Egypt. For the 

 fonner the period is fixed as between the 1st March and 

 the 15th July; whereas for the latter, the period will extend 

 from the 1st April to the 31st July. This arrangement is 

 necessary owing to the difference of climate in the two 

 regions. The further south we go the higher is the tem- 

 perature, and the earlier the demand for the increased supply 

 of water. In addition to this it is to be recollected that the 

 relief afforded by the arrival of the early flood is felt sooner 

 in Upper, than in Middle, Egypt, which latter more nearly 

 approaches the lower province in its agricultural conditions.* 



* Report, pp. 9-16. In tlie history of Joseph we read, Gen. xh, that 

 seven fruitful years preceded seven years of famine in Egypt. May not 

 this have been brought about by periods of abundant Nile flood followed 

 by short floods, each of seven years' duration ? 



