RAINY WEATHER DISASTROUS. 



57 



At Salton, out of the twelve years recorded, only one had more than 

 one-tenth of an inch of rain during the two months of the flowering 

 season (April and May) and only two had over 0.28 inch rainfall 

 during the ripening season. 



At Mammoth Tank, out of these twenty-three years, only one had 

 more than three-tenths of an inch rainfall during the flowering 

 season (April and May) and only three showed over three-tenths of an 

 inch precipitation during October and November. 



At Biskra, in the Algerian Sahara, the rainfall records are available 

 for the ten years from 1884 to 1893. During this period only one 

 month during the critical periods was rainless, viz, October, 1893. 

 Only once during the flowering period (April and May) was there 

 as low as 0.39 inch rainfall, and only once during the season when the 

 fruit ripens (October and November) was there as low as 0.31 inch of 

 rain. 



At Ayata, some 100 miles south of Biskra, in the Oued Rirh country, 

 where a specialt} r is made of the culture of choice Deglet Noor dates 

 for the export trade, the rainfall for 1889 was 2.52 inches; for 1890 it 

 was 9.32 inches; for 1891, a 4.16 inches; for 1896, 7.60 inches; for 1897, 

 4.84 inches; for 1898, 2.79 inches, and for 1899, 6 2.91 inches, an aver- 

 age of 4.89 inches. 



The distribution of the rainfall at Biskra and Ayata, by seasons, in 

 comparison with the average at Yuma in the Colorado River Valley 

 and Salton and Mammoth Tank in the Salton Basin, is given herewith: 



TABLE 7. Table showing seasonal and annual rainfall at stations in desert regions. 



a During the years 1896 to 1899 almost no rain fell in summer. April, May, September, and October 

 are sometimes rainless. 



It is noticeable that the summer rainfall is considerably higher at 

 Yuma and at the Salton Basin stations than at Ayata, but that the 

 spring and autumn precipitation is much less, rendering the climate 

 decidedly more favorable for date culture. 



It is clear from the above tables that there is less danger from rain 

 to date flowers or to the ripening fruits in the Arizona deserts or in 

 the Salton Basin in California than at Biskra in the Algerian Sahara, 

 where date culture is an established and profitable industry. Indeed, 



Holland. Hydrologie du Sahara, p. 416. For the years 1889 to 1891, inclusive. 

 & Records of Cornu exhibited at Paris Exposition, 1900. Amounts read from curves 

 of charts for the years 1896-1899. 



