518 CAUSES OF THE INUNDATIONS. 



the mighty waterfloods created by the southern rains 

 continue their forward course towards the ocean and 

 pour down along the Nile channel, charged with the 

 fertilizing mud of the tropical plains, to spread it over 

 the land of Egypt, and thus bring incalculable blessings 

 to remote lands and their inhabitants, in regions where 

 rain seldom falls. 



At Cairo for instance the average annual rainfall 

 does not exceed about one inch, and in Upper Egypt rain 

 seldom falls at all; what is called a shower often 

 consists of only a few heavy drops, though the sky 

 may be black with what look like rain clouds, and 

 hough thunder peals with ominous vehemence. 



In the equatorial regions, as we have pointed out 

 elsewhere, the rains are almost continuous throughout 

 the year. Rivers therefore which flow from thence, 

 flow for ever, from sources that are exhaustless; and 

 so, in the case of the Nile, the great river has over- 

 come the thirsty sands, and has continued throughout 

 uncounted ages to flow without ceasing through a 

 region comprising the greatest and driest deserts in 

 the world. 



Sir Samuel Baker has described in graphic terms 

 the wonderful phenomena which accompany the 

 bursting of the monsoon upon the Abyssinian high- 

 lands: 



" No one (he says) could explore these tremendous torrents, 

 the Stetite, Royan, Angrab, Salaam, and Atbara, without at 

 once comprehending their effect upon the waters of the Nile. 

 The magnificent chain of mountains from which they flow, 

 is not a simple line of abrupt sides, but the precipitous slopes 

 are the walls of a vast plateau, which receives a prodigious 

 rainfall in June, July and August, until the middle of Sep- 



