266 



POMOLOGY 



versally the lowering of the sap concentration (from any 

 cause) has lowered the freezing point: 



Table LXXIX 



relation of sap concentration to freezing 



young fruits 



Depression 



Cherries fresh from tree 



Cherries from twigs with ends in glycerine sixteen hours. . 



Cherries wilted five hours 



Peaches fresh from tree 



Peaches from twigs with ends in glycerine sixteen hours . . 



Peaches wilted five hours 



Apples from twigs with ends in glycerine thirty hours. . . . 



Apples from twigs with ends in water thirty hours 



Apples from twigs with ends in cane sugar thirty hours. . . 

 Apples from twigs with ends in glycerine forty-eight hourt- 



0.905 

 1.180 

 1,075 

 0.965 

 1.230 

 1.085 

 1.408 

 1.335 

 1.530 

 1.417 



Thus it will be seen from these data that wherever the 

 sap concentration of young fruits has been lessened, the 

 temperature at which it will freeze has been reduced also. 

 The same results were secured with the leaves and tender 

 shoots of trees and with more succulent plants such as corn 

 and tomato. Furthermore, it was shown that the sap con- 

 centration of shaded plants is lower (i. e., not so dense) 

 than that of unshaded ones and hence they kill at a higher 

 temperature. However, all of these researches were con- 

 ducted with succulent plants, and not with woody tissue 

 in the dormant or resting-period. 



