1911.] PUBLIC DOCUMFAT — No. 31. 183 



tcrniined by inouiitaiu ranges and other topographic features, by 

 the temperatures of bodies of water over which the air may 

 liave passed, and perhaps by other considerations. 



The prevalence of a large proportion of sunshine will operate 

 to raise the temperature in the orchard. The effect on the 

 protoplasm of the tree will, owing to the heat absorptive powers 

 of the dark colored bark, be even greater. This has been shown 

 by Whitten. He also found that in peaches the color of the 

 bark modifies in a marked nunmer the thermal effect of the sun.^ 

 The temperatures on which this work is based were presumably 

 all taken in the regulation shelters of the Weather Bureau, 

 where this effect would be less than in the orchard. The prob- 

 able amount of sunshine should be taken into consideration in 

 estimating the summer mean of an orchard. 



III. THE DEVELOPMENT OF THE APPLE. 



For convenience in discussion, the life history of the apple 

 (fruit) may be somewhat arbitrarily divided into four periods: 

 (1) that of growth, which extends from the blossom to the 

 attainment of full size; (2) that of ripening, which covers the 

 period from the termination of the first until the apple is picked 

 from the tree; (3) that of "after ripening," extending from 

 picking until the apple is in perfect eating condition; and (4) 

 that of decay, covering the subsequent deterioration and break- 

 ing down of the fruit. Various fungous diseases may enter in 

 during these periods and terminate the life of the apple at any 

 time. These are not considered in this discussion. The second 

 and third periods are scarcely differentiated in summer apples, 

 these being ordinarily fit for immediate consumption on ])ick- 

 ing. In winter apples, on the other hand, there is a distinct 

 period of ripening following the picking of the fruit. 



Inasmuch as the discussion of these periods of growth will be 

 largely from a chemical standpoint, it may be well to consider 

 briefly the chemical composition of apples before discussing 

 their development. 



Apples vary widely in chemical composition, according to 

 \ariety, stage of development and conditions of growth. They 



• Report American Pomological Society, 26, p. 47 (1900). 



