WATER SUPPLY. 17 



The plats of vegetables that are irrigated from wells in the date 

 gardens are situated on terraces constructed in the side of the sand 

 hills, usually 10 feet or less above the floor of the basin. (PL III, 

 figs. 1 and 3.) The well water is raised by hand in a shallow bucket, 

 generally made of basketware covered outside with pitch, but some- 

 times of goatskin, which is hung on the small end of a slender palm 

 trunk and counterpoised by a piece of rock fastened to the large end. 

 The pole is fastened by its center to a crosspiece that is supported by 

 two vertical posts made of stouter palm logs or of cemented rock. The 

 bucket is emptied into a little cement basin adjoining the well curb, 

 whence the water flows through a system of small conduits into the 

 plats that are to be irrigated. Flood irrigation alone is practiced. As 

 there is no soil in the region from which ditch banks and ridges that 

 Avill stand up when wet can be made, the conduits and ridges of the 

 plats, as well as the lining and curb of the well, are made of the 

 same clark-gray plaster with which the walls of the houses are 

 cemented. Plugs of wool are used for stopping the conduits at places 

 where water is to be diverted into the plats. Among the vegetables 

 jnost commonly grown are cabbages, turnips, radishes, carrots, pump- 

 kins, melons, watermelons, onions, tomatoes (a small-fruited sort), 

 and peppers. 



In parts of the Souf region, especially east of the capital town, 

 El Oued, the water of the wells is said often to contain enough mag- 

 nesium and other salts to make it disagreeable for drinking." West 

 of the town, on the other hand, the water is said to be generally very 

 pure. Tlie difference is thought to be sufficiently great to have a 

 marked effect upon the quality of the dates, the most renowned 

 Deglet Noors of the Souf region being produced near the village of 

 El Amiche, where the water is purest. The peculiar character of 

 the water supply of the Oued Souf is not without advantages. Emi- 

 nent authorities are of the opinion that the underground sheet is 

 abundant and that it is much less liable to exhaustion than in the 

 Oued Rirh, where numerous flowing artesian wells exist. 



o Well water in the Souf. according to an analysis cited by Jus (Les oasis 



du Souf du Departenient de Constantine. Rul. Acad. d'Hippone, No. 22, p. 67 



(1880), has the following contents of .solid matter in grams per liter of 



water : 



Sulphates 1. 099.5 



Chlorids . 7769 



Carbonates . 2999 



Nitrates and dissolved organic matter .0690 



Silicates, etc., in suspension . 0335 



Total 3. 1786 



Schirnier (Le Sahara, p. 261) states that the mean salt content of well water 

 at El Oued is 2.77 grams per liter. 



