CLIMATE. 25 



tilling the air with the fine dust it carries. It often does great harm to 

 crops, vineyards and ripening grain being particularly liable to injury. 

 The sirocco also blows in winter, but its violence is less at that season 

 and it is cooler and moister. The regular summer wind is, however, 

 the sea breeze from the northeast, which springs up every morning 

 and is of great importance in moderating the temperature. East 

 winds are also frequent in summer. At night, on the other hand, the 

 prevailing wind is from the south. Absolute calm is not infrequent. 

 In proportion as we travel farther from the coast, the effect of winds 

 from the sea becomes less perceptible and that of the desert winds 

 more pronounced. This difference becomes strongly marked after the 

 northern mountain system is crossed. 



The sirocco is the most striking climatic feature in which Algeria 

 differs from California. In southern California a wind from the des- 

 ert, known as the ''Santa Ana" wind, blows occasionally, but induration 

 and severity it is not to be compared w4th the Algerian sirocco. 



HIGH PLATEAU REGION. 



The small agricultural importance of the high plateau region makes 

 it unnecessary to discuss its climate at any great length. Owing to 

 its greater elevation and distance from the sea, conditions are more 

 extreme than in the coast region. The winters are colder and the 

 summers hotter. Winter temperatures as low as 7" F. have been 

 known, while in summer a temperature of 105*^ F. is often experi- 

 enced. Daily variations amounting to 85 degrees have been recorded. 

 In its severe winters the high plateau region resembles the highest alti- 

 tudes of the mountain zone of the coast region, but differs in its hotter 

 temperatures in the daytime in summer. In the latter respect it 

 resembles the desert region, but there the nights are warmer in sum- 

 mer and the winter is much milder. Battandier and Trabut« mention 

 one point in the high plateau region, at an elevation of about 4,700 

 feet, where the mean temperature for ten years was about 44.-5^ F. in 

 winter, 55.5 F. in spring, 79- F. in summer, and 62 ^ F. in autumn. 

 The yearly mean temperature was 62^ F. 



The rainfall is much less than in the coast region, but no exact data 

 on this point are available. Rain falls usually in sudden and violent 

 showers. Storms are more frequent during the summer than is the 

 case along the coast. The amount of precipitation is trivial, although 

 sometimes sufficient to moisten the ground. Durmg the winter the 

 soil, especially in depressions, contams enough water in occasional 

 years to bring a crop of barley without irrigation. The atmospheric 

 huraidit}^ is almost always very small. 



aL'Algerie, [k lis. 



