CLIMATE. 19 



southern slopes and the high plateau region beyond are quite arid. 

 What moisture passes across the mountains of the first system is 

 largely withdrawn from the atmosphere when it reaches the second, 

 which bounds the steppe region on the south. Consequently, the 

 desert beyond receives an insigniticant share of atmospheric moisture 

 from the Mediterranean. 



Winds that come from the opposite direction — out of the Great 

 Sahara — are, of course, at all seasons extremely dry. It is in late 

 summer — especially in September^that the dreaded sirocco, the hot, 

 sand-laden wind of the desert, is strongest and most frequent. Then 

 it blows for days at a time over the high plateau and the two moun- 

 tain ranges that form its boundaries, into the Tell, and even across the 

 Mediterranean into southern Europe. 



The three principal physiographical regions coincide with the most 

 important climatic regions of the colony. For a further examination 

 of this subject it will therefore be advisable to take up each in its turn, 

 beginning with the coast region, or Tell. 



In the tables given below, climatic data from Algerian localities are 

 copied from Thevenet's ''•Essai de Climatologie Algerienne."" For 

 comparison, data from various places in the western United States 

 where similar conditions obtain are also included. These are taken 

 from publications of the United States Weather Bureau. Much infor- 

 mation regarding the climate of Algeria has also been drawn from the 

 excellent little work of Battandier and Trabut, previously mentioned. 

 Owing to the paucity of accurate records and the small agricultural 

 importance of the high plateau region, no tables are given for that part 

 of the colon}". It should be remarked, however, that Setif, which has 

 an elevation of 3,560 feet, although here included in the tables for the 

 coast region, is sometimes considered as belonging to the high phiteau, 

 and the climatic data from this point are doubtless fairly applicable to 

 the uncharacteristic eastern portion of that region. Again, Bou 

 Saada, figures from which localit}^ are given in the tables of climate 

 of the desert region, really belongs to the extremely desert-like portion 

 of the high plateau. 



COAST REGION. 



TEMPERATURE. 



The littoral zone of the coast region has a mihl winter, resembling 

 that of the California coast. Temperatures at noon of 70^ to 75- ¥. 

 for fifteen days or a month at a time are not of rare occurrence in 

 winter. The temperature never descends much below freezing, and 

 does not remain at that point for an}' length of time. Still, tempera- 

 tures of 23^ F. , such as are sometimes recorded by thermometers placed 

 4 inches above the surface of the ground, can do considerable damage 



