10 



BOTANICAL FEATURES OF THE ALGERIAN SAHARA. 



rainfall and the total evaporation, based on the official climatic reports. 

 In tables 6 and 7 the report for the year 1908 is used. The figures repre- 

 sent the ratio f-j between evaporation and rainfall, in which the amount of 



evaporation is used as the numerator and the amount of precipitation as 

 the denominator. In the monthly evaporation-rainfall table (table 6), in 

 all cases where no rainfall was reported for the month it was called i mm. 

 In table 7, however, which gives the seasonal evaporation-rainfall ratio, 

 the actual figures of the government report were in all cases employed, 

 since there was no season during the year 1908, even in southern Algeria, 

 when no precipitation occurred.* 



Table 6. — Evaporation-rainfall ratio, monthly, 1908. • 



Station. 



Nemours 



Cape Falcon . . 



Oran 



Algiers 



Bouzarea 



Maison-Car^e . 

 Ft. National . . 

 Sidi-bel-Abb^s 



Saida 



Batna 



Tebessa 



Bou Saada. . . . 



Barika 



Ain Sefra 



Gery ville 



Laghouat 



Ghardaia 



El Oued 



Jan. 



1.07 

 i-S 

 1.3 

 0.63 

 0.57 

 0.72 

 0.72 

 0.63 

 0.67 

 1.6 

 4.6 

 4-OS 

 2.4 

 9.2 

 6.3 

 309 

 8.9 

 S3.9 



Feb. 



1-3 



1.8 



1.9 



1.3 



0.67 



0.64 



0.29 



0.76 



0.64 



2.3 



6.0s 



S.4 



8.7 



21. S 



1.9 



4-7 



233.0 



27.7 



Mar. 



Apr. 



39 I 



46 16, 

 6 I 



S 

 22 



I 

 o 

 I 

 o 

 I 





 2 



3 

 2 

 5 



i 23 

 I 23. 

 203 

 529 

 '629 



Nov. Dec. 



10.6 

 8.9 

 3-4 

 1.2 

 0.76 

 0.35 

 0.71 

 1-9 



1.2 

 2.6 



3.5 



5.6 



90.6 



13.2 



4.1 



154-0 



49-7 



215.0 



5-7 

 2.2 

 4.4 

 I.I 

 0.5 

 o.si 

 0.16 

 0.8 

 0.78 

 1.6 

 3.7 

 8.3 

 1.3 

 1.2 

 3.9 

 104.0 

 225.0 

 123.0 



Table 7. — Evaporation-rainfall ratio, seasonal, 1908. 



Station. 



Littoral: 



Nemours 



Cape Falcon 



Oran 



Algiers 



Bouzarea 



Maison-Car^e . 



Tell: 



Ft. National . . 

 Sidi-bel-Abb^s 



Saida 



Batna 



Tebessa 



High Plateau: 



Bou Saada. . . . 



Barika 



Ain Sefra 



Gery ville 



Desert: 



Laghouat 



Ghardaia 



El Oued 



Winter. Spring. 



2.69 



1.83 



2.54 



i.o 



0.58 



0.62 



0.39 



0.73 



0.69 



1.8 



4-7 



5-9 

 4.1 

 1.4 

 7.0 



6.0 



154-9 

 68.3 



44.09 

 8.75 

 3.7 

 7.96 

 3.0 

 S.o 



1-4 

 8.2 

 i.o 

 2.1 

 4.0s 



7.0 



6.6 



la.s 



9.8 



73.2 

 416.3 

 354-0 



Summer. 



24.1 

 S8.6 

 71.0 

 86.4 

 28.S 

 117.4 



83-2 



38-3 



3-5 



0-3S 



88.3 



76.0 

 93.S 

 67.9 



30.8 



271.6 

 293.7 

 485.3 



Autumn. [ Annual. 



When we reduce the evaporation-rainfall ratios of the different physio- 

 graphic provinces to simple expressions we gain a comprehensive view of 



* At Tou,s:gonrt, however, no rain was reported during the summer season of 1908. 



