LOCUST DESTRUCTION. 



159 



process adopted in a part of the country intersected by 

 open irrigation channels. Eough screens made of reeds 

 are set up along one side of the watercourse, as shown in 

 the annexed cut, and the inactive insects, being driven 

 against them, fall into the water and are drowned. Some 

 effect may doubtless be produced by these contrivances ; 

 but it seems very doubtful whether, if every locust that 

 reaches the inhabited districts were destroyed, the plague 

 would be materially abated. In a region including wide 

 tracts almost without population there are unlimited 

 opportunities for depositing the eggs ; from these arise 

 countless swarms, which, in their active condition, are 

 capable of traversing wide spaces in search of nourish- 

 ment. The suppression of the locust plague probably 



awaits the spread of some creature to which their eggs 

 would afford suitable food. 



In great measure influenced by Washington's account 

 of his visit to Tasseremout, and his conviction that from 

 that place the highest ridge of the Atlas might be reached 

 in a single day's excursion, we had decided on making that 

 our first halting-place ; and, as the distance can be little 

 over twenty miles, we reckoned on reaching it by evening. 

 Our way lay about due south-east through the district 

 of Mesfioua, which is under the rule of a Kaid, or sub- 

 governor, subject to the orders of El Graoui. 



To the eye the country seems a dead level ; but the 

 rapid flow of water in the covered channels and smaller 



