30 AGRICULTURAL EXPLORATIONS IN ALGERIA. 



but an insignificant stream in summer. Rainfall is too scanty, even 

 at a short distance from the coast, to feed large rivers. For this 

 reason irrigation in Algeria nmst necessarily be on a more modest 

 scale than in P^gypt. As a matter of fact, the area under irrigation 

 at present is only a small fi-action of the total area of the colony. 



The littoral zone of the coast region, particularly in the eastern part 

 of the colony, receives quite enough precipitation in winter for the 

 growing of most crops. In summer, however, there are very few 

 parts of Algeria where field crops can be grown without irrigation, 

 at least without a radical change in the methods of cultivation gener- 

 ally followed in the colony. Orchards and vineyards, however, can 

 be made to pay in some places without artificial watering. This is 

 notal)ly the case in the mountain zone, where steep slopes, ill adapted 

 to irrigation, are covered with fruit trees. In the valley and plain 

 zone of the coast region irrigation is almost indispensable in summer, 

 and even the winter cereal and forage crops are greatly benefited by 

 an occasional watering. In the high plateau region nothing can be 

 grown in summer without irrigation, and in winter it is only in an 

 occasional depression that the natural moisture is sufficient to bring a 

 crop. In the desert region artificial watering is at all times necessary 

 for small crops, although sometimes it is of the simplest character. 

 Thus, at the base of the mountains scanty crops of grains can be pro- 

 duced by throwing up a series of ridges to retain the sheets of flood 

 water that in winter occasionally sweep down over the land. 



There is no reason to believe that in ancient times, when north- 

 ern Africa was the granary of the civilized world, conditions as to 

 water supply were essentially diflerent from those now prevailing, 

 although there is evidence that, in eastern Algeria at least, crops were 

 much more extensivel}^ grown without irrigation than is now the case. 

 Under the Carthaginian regime, and later under the Roman rule, irri- 

 gation works abounded in the country that is now Algeria and Tunis. 

 The remains of such structures, sometimes utilized as foundations for 

 modern works, are numerous, particularly in the Depailment of Con- 

 stantine and in Tunis. Indeed, more than one region that is now a 

 barren desert must have been well populated and in a high state of 

 cultivation two thousand years ago. 



The works built at that period were generally of the simplest and 

 rudest construction. Often merely a mass of earth or broken stone, 

 held in place by a row of stakes, served to dam a small brook. For 

 the most part these structures wei-e evidently the work of the colo- 

 nists who tilled the land under them, rather than of trained engineers. 

 The}^ were built sometimes by individuals, sometimes by associations. 

 The plan usually followed was to dam up a mountain torrent near the 

 point where it debouches upon the plain. In narrow ravines a succes- 

 sion of rough dams was often constructed, thus allowing the stream 



