COMPOSITION OF CALIFORNIA LEMONS. 17 



of the year, the Eureka variety contains the greater amount of acid; 

 during the last six months, the reverse holds true. 



COLOR AND THICKNESS OF PEEL. 



Apparently little correlation exists between the color and com- 

 position of the fruit. The data were carefully selected so as to omit 

 those from samples containing too great a mixture of colors to be 

 accurately estimated. 



The better part of both varieties had peel of medium thickness, 

 but the Eurekas had a larger percentage of thin-skinned fruit and a 

 smaller one of thick-skinned than the Lisbons (Table 8) . 



Few conclusions can be drawn from these data. Where some corre- 

 lation may exist in one of the varieties, it fails to show with the other. 

 For instance, the Eureka seems to decline in specific gravity as the 

 color lightens, but the Lisbons show no such tendency. Likewise, 

 the acid seems to increase with the Lisbons as the color decreases, 

 but this is not apparent in the case of the Eurekas, although the dark 

 green and full yellow correlate. 



Classifying the samples according to thickness of skin, 26 thick- 

 skinned, 49 medium-skinned, and 13 thin-skinned Eurekas were 

 found, and 21 thick-, 30 medium-, and 3 thin-skinned Lisbons (Table 

 8). Unfortunately there are too few thin-skinned Lisbon samples to 

 render the results under this particular head of value, and no account 

 is taken of them in discussing the data. 



Two correlations seem apparent from these data: (1) The specific 

 gravity increases as the thickness of the peel decreases; and (2) the 

 acidity of the fruit increases as the peel decreases. Both seem in 

 line with what might be supposed would take place. Thick-skinned 

 fruit often has a hollow center and is generally coarser than that with 

 thinner peel. Inasmuch as the peel contains no acid, naturally the 

 fruit having the greatest amount of peel is likely to contain the least 

 amount of acid. As the oil-bearing part of the peel is near its sur- 

 face and does not correspond in any way with the thickness, it would 

 hardly be expected to change. 



EFFECT OF LOCATION. 



It was thought at first that the data obtained in this investigation 

 might throw some light upon the effect of environment on the com- 

 position of the fruit. Locations near the coast as well as in the inland 

 valleys were selected, and if any marked difference in composition 

 between lemons from the two sections existed it should have been 

 revealed. The 10 Eureka locations were equally divided as to situ- 

 ation, 5 being on or near the coast and 5 inland or separated from the 

 coast by ranges of hills. What at first appears to be a slight difference 

 in the results (Table 11) is found in the oil content of fruit from the 



