22 CALIFORNIA FRUITS: HOW TO GROW THEM 



wholly unknown in the interior where the air is drier. The dry air 

 also favors the access and action of light and heat, for Tyndall says 

 that a sheet of vapor acts as a screen to the earth, being in a great 

 measure impervious to heat. 



It is not necessary, then, that there should be clouds to lessen the 

 chemical effects of sun heat in fruit ripening. Not only do clouds 

 intercept sunshine, but water vapor in the air when to the eye the 

 sun is bright as ever can absorb a large quantity of the effective 

 sun rays, and so retard fruit ripening. Hence an apparently sunny 

 country which has much invisible vapor in the air, may prove de- 

 fective in fruit-ripening qualities. 



It is true that air free from humidity allows rapid escape of heat 

 by radiation as well as free access of it, and in the dry air frost is 

 more severe, but at the time of the greatest fruit growth, from June 

 to October, radiation down to a frost point is prevented by other 

 natural agencies. In the early spring and late autumn the humidity 

 percentage rises again and checks radiation just at the time of the 

 year when it is most desirable to have it checked. 



The accompanying table, compiled from the records of the United 

 States Weather Bureau, shows the prevailing relative humidity in 

 the East and South and in California. 



Normal Relative Humidity at Eastern and California Points 



Avg. for 



Eastern Stations April May June July Aug. Sept. Oct. Nov. 8 mo. 



Jacksonville Fla 72.3 73.0 77.6 78.6 80.9 82.9 79.8 82.2 78.4 



Philadelphia Pa 63.4 68.9 69.2 68.6 71.2 75.2 70.7 73.6 70.1 



Rochester, N. Y 67.8 68.6 69.1 67.3 70.7 75.2 75.6 76.2 71.3 



Grand Haven, Mich 70.9 71.4 73.7 69.0 73.1 75.0 75.7 79.1 73.5 



St Louis, Mo 63.7 67.8 68.8 66.3 67.3 70.2 65.9 71.1 67.6 



New Orleans, La 76.0 74.2 78.1 78.3 78.8 77.3 74.0 79.4 77.0 



Galveston, Tex 84.6 78.0 79.3 77.4 78.1 77.2 75.6 80.4 78.8 



Lo?Angeles StatK !.... 73.1 75.2 73.0 75.4 76.2 72.9 74.3 66.6 73.7 



Fresno 59.3 52.7 42.4 34.7 34.7 43.6 55.1 64.1 48.3 



Sacramento 67.6 67.6 66.1 59.8 59.8 59.0 62.4 66.8 63.6 



Red Bluff 61.9 56.8 43.7 35.6 35.3 43.6 51.6 60.7 48.6 



The three great advantages of the California climate abundant 

 heat, continuous sunshine, and dry air taken in connection with 

 the fitness of the soil and the great length of the growing season, in- 

 sure the characteristic excellence of California fruit, and the early 

 maturity, great growth, and abundant fruitage of our trees and 

 vines. Heat, sunshine, dry air, and a rainless summer also minister 

 directly to the curing of fruits in the open air. 



A RECAPITULATION OF CALIFORNIA'S CLIMATIC 



ENDOWMENT 



Through the multitude of local observations, which seem per- 

 plexing and almost contradictory, it is possible to clearly discern 

 certain general conditions of both nature and culture, which may be 

 briefly advanced as characteristically and distinctively Californian. 



