19(3 NATIVE SKILL IN IRRIGATION. 



ai. Till, 



miles lower down, and a rocky bed full of deep holes through 

 which it was not quite easy to take our horses and mules. 



Throughout the valley we were struck by the proofs of 

 native industry and skill given by the numerous irrigation 

 channels, such as one sees in Piedmont, and in the tribu- 

 taries of the Rhone valley in Switzerland, sometimes cut 

 along steep faces of rock, sometimes maintained by high 

 terraced banks. Where the ground is favourable, walnut 

 trees are often planted along these watercourses, and must 

 largely contribute to the dietary of the inhabitants. It 

 thus appears that the drainage of the Great Atlas is, in 

 great part, absorbed by irrigation, even before the streams 

 enter the low country, while a further portion is there taken 

 up for the same purpose, and but a small percentage reaches 

 the sea in ordinary weather. This helps to account for much 

 that at first sight appears so strange in the hydrography of 

 Marocco. A vast mountain region, fully exposed to the 

 currents of saturated warm air from the Atlantic, sends 

 but four rivers to the ocean from its northern and western 

 flanks, in a coast line of over 400 miles from El Araisch 

 to Cape Guer ; and these, at ordinary times, are all easily 

 fordable. But when rain falls on the mountains, the irri- 

 gation channels are speedily filled to the brim, and the 

 entire surplus reaches the rivers, which are then said to 

 rise ten or twelve feet in the course of as many hours. As 

 bridges are unknown, the Moors speak of travellers being 

 detained for many days before a flooded river channel, as 

 a common occurrence. 



Above the ford, the valley was again contracted to a 

 mere gorge, and the narrow path mounts on its eastern 

 flank, and winds along the extremely steep rugged slopes 

 much after the fashion of some unfrequented valley of the 

 Southern Alps. Although the sun was already high, the 

 mountain rose so sheer upon our left that the shadow often 

 gave welcome protection ; and the track was so narrow in 

 places that we were not free from anxiety for the baggage 

 animals. 



