EXAMPLES OF DEOUGHT RESISTANCE. 



11 



Table I. — Average rainfall by months and annual average for Casa Grande, Phoenix, 

 Maricopa, and Mesa, Ariz., for the years from 1897 to 1908, inclusive.^' 



a The figures of this table were kindly furnished by Mr. L. N. Jesunofsky, section director, Weather 

 Bureau, Phoenix, Ariz. 



6 Ttiese means were obtained by substituting the mean of the month specified in places where the record 

 was wanting. 



Figure 2 shows graj^hically the average rainfall by months for Casa 

 Grande, Ariz., and adjacent stations, from 1897 to 1908, inclusive. 

 The two periods of greater rainfall each year, one culminating in 



Soefre^fr ar/ 



Fig. 1.— Map showing the points in Arizona and southern California where dry-land olive growth was 



studied. 



August and one in November, with ^May aiul June nearly rainless, 

 are characteristic of the region. 



The range of temperature during the year is from a minimum of 

 25° or 28° F., with occasional years as low as 17°, to a maximum of 

 117° to 122° F. The mean relative humidity recorded for Phoenix 

 in Table II and grai)hically illustrated in figure 3 wall not be far 

 from correct for the Casa Grande region. 



Table II. — Mean monthly and mean annual relative humidity of Phoenix, Ariz., for 



the years 1905, 1906, and 1907. 



192 



