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 
