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UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



This arrangement eliminated the personal equation in tree selection, 

 care being taken that the trees of a given variety were of the same 

 general type. Great care was also used to prevent other influences 

 on production than the heating methods used from interfering with 

 the results. Naturally, all observable influences on individual tree- 

 production which might tend to interfere with the results or modify 

 them were considered in locating the plots. From our experience 



Fig. 22. The effect of the freeze on unheated Eureka lemon tree. Such 

 trees have since recovered, but two years' crops were lost. 



with these plots since their selection, we feel sure that the results 

 represent fairly the influences of heating as compared with no heating. 



The crops from all the trees were picked at regular intervals for 

 one year. After completing one year's data, it was decided that it 

 was unnecessary to continue records in all of the plots for a second 

 year. Two plots, one heated and one not heated, were selected for 

 the second year's data, and records from all of the other plots were 

 discontinued. The difference in production between the heated and 

 unheated plots was found to be considerable the second year. 



During the experiment each tree was picked separately. The fruits 

 were sorted into four grades green, tree-ripe, frozen, and culls. 



