THE EXAMPLE OF ROME 189 



do not feel the full effect of a given rainfall for two or three years. 

 Jerusalem is added for comparison. 



Groups of Years 



I. 7 years with heaviest rainfall in California. Average 6.5 inches 

 and over at San Francisco and San Diego combined. 

 II. 18 years with heavy rainfall in California. (3.9 to 6.4 inches.) 



III. 17 years with light rainfall in California. (2.7 to 3.8 inches.) 



IV. 13 years with least rainfall in California (less than 2.7 inches). 



I. 



II. 



HI. 



IV. 



San Francisco 

 and San Diego 



8.3 



4.6 



3.4 



1.9 



Average Rainfall 

 B C 



Naples 



11.5 



11.0 



9.2 



8.6 



Rome 



10.7 



10.6 



9.8 



9.6 



Average Growth of Trees 



D E F 



Jerusalem S Years Third Year 



7.0 3.02 3.07 



6.3 3.00 3.04 



5.6 2.98 2.99 



5.2 2.92 2.84 



Without exception all the columns from B to F vary in harmony 

 with A. At Rome the agreement with California is less marked 

 than at Naples, while at Naples, when reckoned in percentages, 

 it is less noticeable than at Jerusalem. At Palermo in Sicily, 

 however, the agreement is probably at least as marked as at 

 Jerusalem, as appears from the following table for the twenty-six 

 years for which records at Palermo are available at the time of 

 Writing. 



(1) 10 years averaging 5.8 inches in California average 8.3 at Palermo 



(2) 8 years averaging 3.6 inches in California average 7.6 at Palermo 

 (8) 8 years averaging 2.4 inches in California average 6.2 at Palermo 



From these facts it seems quite clear that the curve of tree 

 growth in California can safely be used as an approximate 

 measure of the storminess in the southern half of Italy. Turning 

 now to Figure 24 we see that from about 450 to 250 B. C, Cali- 

 fornia, and presumably Italy, was blessed with much more rainfall 

 than at present. During those two centuries the Big Trees grew 



