SWEET-POTATO STORAGE STUDIES. 
15 
The sweet potatoes in the bins were kept longer than those in 
crates. If the latter had been kept the full length of time (lTl^J 
days) the shrinkage would have been a little greater, since during 
the last month of storage the average shrinkage of the three varieties 
at 55° to 60° F. was a little more than 1 per cent, as shown in Table 
6. The results with the Nancy Hall are for one year only, since 
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THERMOGRAPH SHEET FOR THE PERIOD A~B. 
Fig. 3. — Diagrams showing the temperature in the interior of the bins (solid lines) as 
compared to the temperature of the air (broken lines) in 1918-19 at the Arlington 
Experimental Farm, Va. The upper diagram gives the average temperature for the 
storage season, by weekly periods. The middle diagram gives the same data by daily 
averages. In these diagrams each square indicates a period of seven days. The lower 
diagram is a typical thermograph sheet, in this case for the period A-B. 
there was no bin test of this variety in 1917-18. The shrinkage of 
this varietv was low in both the bins and crates in 1918-19. 
RELATION OF THE TEMPERATURE IN THE BINS TO THE TEM- 
PERATURE OF THE SURROUNDING AIR. 
Air-soil thermographs were employed to ascertain the differences, 
if any, between the temperature in the center of the bins and the 
temperature of the air in the storage house. Figures 3 and 4 show 
