548 
Journal of Agricultural Research 
Vol. V, No. 13 
Table II .—Percentage composition of halves of sweet potatoes kept for various times 
under different conditions — Continued 
STORED IN 5 ° C. CHAMBER PROM OCT. 17 TO NOV. II 
No. of 
sweet 
potato. 
89a 
89b. . . 
95a .. . 
95b... 
Moisture. 
Reducing 
sugar as 
glucose. 
Percentage 
of difference 
between 
halves. 
Cane 
sugar. 
Percentage 
of difference 
between 
halves. 
Starch. 
Percentage 
of difference 
between 
halves. 
76.30 
2*35 
76.32 
2*35 
75 - 79 
2. 22 
75 - 7 i 
2. 22 
7 S -98 
2. 6l 
75-97 
2. 6l 
76. l6 
2. 57 
76. 21 
2. 52 
5*5 
2. 5 
4*35 
4 * 38 
4.48 
4*47 
3 * 97 
3 * 95 
3 * 67 
2. 5 
12. 02 
12. 02 
12. 38 
12. 60 
12. 44 
12. 40 
12. 48 
12. 45 
3*9 
*4 
The results indicate that the longitudinal halves of sweet potatoes 
which have been stored for a time are likely to show a greater dissimi¬ 
larity in, composition than the halves of freshly dug potatoes. The dif¬ 
ferences, however, are not sufficiently great to overshadow the significant 
differences seen in the later tables. The inequality in composition of the 
halves of the same potato is much less than the unlikeness of different 
potatoes. The method of comparison of halves is therefore more satis¬ 
factory than the comparison of different whole potatoes unless a suffi¬ 
cient number be used to obliterate, to a great extent at least, errors due 
to individual differences. 
The question whether the cut halves behave in the same way in storage 
as whole sweet potatoes can be more easily discussed in connection with 
the data presented later. It should be mentioned here, however, that in 
the first experiment at 15.5 0 C. the halves lost an unusual quantity of 
moisture and that this drying may have had some influence on their 
behavior. In subsequent experiments precautions were taken to avoid 
a loss of moisture as far as possible. 
EXPERIMENTAL DATA 
The data relating to all the experiments are collected in Tables III, 
IV, and V. Table III contains the data of the three experiments con¬ 
ducted at 30°, Table IV those of the experiments at 5 0 , and Table V 
those of the experiments at 15.5 0 C. Under each experiment the first 
section refers to the changes in composition of the sweet potatoes during 
the first period of 10 to 12 days immediately after the roots were dug, 
while the second section gives the changes during a period of equal length 
immediately following. The change during each period is shown by the 
difference in composition between the “a” halves analyzed at the begin¬ 
ning of their respective periods and the “b” halves of the same potatoes 
analyzed at the ends of the periods. The data in each case are based on 
the water content of the first half of the potato analyzed. The columns 
of differences show, respectively, the difference in the percentage of 
