304 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



classed "unfrozen" and "frozen" according to its appearance on 

 being cut. 



In the fruit picked on January 13, of the fifty-five sound oranges, 

 twenty-nine had a specific gravity of .87 or more. Of the thirty-two 

 frozen ones, seven were also .87 or more. If, therefore, an attempt 

 had been made to separate the sound from the frozen using .87 as the 

 point of separation, twenty-six good fruits would have gone out with 

 the injured ones and seven frozen ones would have been retained. 

 Two weeks later, however, a similar separation would have recovered 

 forty-one good oranges and six frozen ones. At the end of a month, 

 all of the sound oranges had a specific gravity of .87 or above, while 

 all but six of the frozen fruit were below this point. The effectiveness 

 of holding oranges two weeks or a month after picking, before separa- 

 tion, is, therefore, very clearly demonstrated. 



Subsequent picks illustrate the same principle. The most favor- 

 able points of separation are not constant throughout, however, nor 

 is the percentage of recovery absolutely uniform. In the fruit picked 

 on January 18 the separation of the oranges would have been made at 

 .88 two weeks after picking, to eliminate all frozen fruit, and thus 

 five sound ones would have been lost. In fruit picked on January 22 

 the same point, .88, would have eliminated all frozen oranges, but it 

 would also have thrown out twenty-five out of forty-two good ones. 

 Even a separation at .84 would have lost five good ones, while includ- 

 ing fourteen frozen ones. In such fruit a single separation becomes 

 inefficient. By making three grades, one below .83, the other between 

 .83 and .87, and the third above .87, very satisfactory results could 

 have been obtained. By January 25 the frozen fruit on the trees had 

 so decreased in specific gravity that it was possible to eliminate it 

 quite completely. Even at this date, however, it was not possible to 

 prevent some loss of good fruit unless the fruit was kept in storage 

 for some time before the separation was made. In fruit picked on 

 January 25, sixteen of the forty-two good oranges were .84 or below, 

 while there were three frozen ones above that figure. Two weeks later 

 there were still seven good oranges below .84 and five frozen ones 

 above that point. 



The lemons show a much sharper line of demarcation. On the 

 date of picking, January 13, three of the sixty-four good lemons were 

 below .89 in specific gravity and twelve of the forty-four frozen ones 

 were .89 or above. Two weeks later all of the good lemons had a 

 specific gravity of .89 or above and all but two frozen fruits (one of 

 which is shown in, figure 17) were below that mark, so that a very 

 complete separation could have been effected. 



