300 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



SPECIFIC GEAVITY OF FEUITS 



The work done in previous years had shown that the specific 

 gravity of frozen fruit decreases and that the frost markings on the 

 rind are unreliable as a means of separation (fig. 16). It was found 

 through work done by Mr. D. C. Lefferts of Redlands, California, that 

 frozen fruit was usually lighter in weight than sound fruit and that 



Fig. 16. Frozen and unfrozen Eureka lemons showing specific gravity 

 of each fruit. The fruit with a specific gravity of .81 is free from frost 

 markings and is apparently uninjured. It is, however, badly frozen. Photo 

 by Smith, January 24, 1913. 



by immersing a mixture of sound and frozen fruit in a suitable liquid, 

 such as alcohol, the two classes could be separated. As this method 

 of procedure proved to be f airly satisfactory, a machine was con- 

 structed for use in packing houses and a patent granted to Mr. D. C. 

 Lefferts of Redlands and to Mr. George D. Parker of Riverside, cover- 

 ing the principle involved. Following the freeze of 1913 another 

 method of separation, based on the specific gravity of frozen and 

 unfrozen fruit was devised by Mr. Frank Chase of Riverside. (See 

 description, page 297.) 



In view of the great demand for exact information on this subject 

 and because of its economic importance, a statistical study was made 

 of the behavior of a number of oranges and lemons of varying degrees 

 of injury by the frost. 



