198 



THE CLIMATIC FACTOR AS ILLUSTRATED IN ARID AMERICA. 



Fig. 60. — Storm Frequency. September. 



I30' 125* 120" 115° no" 105° 100* 95' 90" 85' 80' 7S' 



70 65 60 55' 



'15 110' 105" 100° 95' 90' 85' 80 75" 70* 



Fig. 61. — Storm Frequency. October. 



