IRRIGATION SYSTEM. 31 



It is evident from this analysis that the water afforded by the 

 springs of Tozer is pure enough to be used with perfect safety in 

 irrigating any crop grown there. As the springs of the other oases 

 of the Jerid have a similar origin to those of Tozer, it is probable 

 that the composition of their waters differs little from the foregoing. 



IRRIGATION SYSTEM. 



Irrigation at Tozer has been brought to a higher stage of develop- 

 ment than elsewhere in the Jerid, and a description of the system in 

 use at Tozer will serve for the other oases as w T ell. a It is said to have 

 been elaborated long ago by an Arab named Ben Chabet, and to have 

 been religiously maintained, unchanged as he planned it, to this day. 



FIG. 2. Irrigation canal and diversion dam, Tozer oasis. 



The details of its management are transmitted from father to son in 

 a certain family. Having perfected the system at Tozer, Ben Chabet 

 offered to do the same service for the inhabitants of Nefta, who were 

 constantly in dispute over their water rights, but their jealousy of 

 Tozer prevented their accepting his offer. "French students of the 

 Tozer system praise very highly the ingenuity and thoroughness with 

 which it has been worked out. 



The main stream which collects the waters of all the springs of 

 Tozer is divided and subdivided by a series of dams made of palm 

 logs (fig. 2) until the water reaches the ultimate divisions or seguias 

 (ditches) which supply each individual garden. The log which 



For a detailed account of this system, see F. Masselot, " Les Dattiers des 

 Oasis du Djerid," Bui. Dir. Agr. et Com. Tunis, 1901, pp. 137-142. 

 92 



