SHKINKAGE OF CORN IN STOEAGE. 9 



Wlien the corn was returned to the scale on May 14, after the third 

 elevation, the temperature of the corn was practically the same as 

 the temperature of the air at the time the corn was handled, which 

 was shghtly less than 55° F. The corn was then held on the scale 

 until June 1 , when the corn was again hot. At this time the experi- 

 ment terminated. During this final period of 18 days the additional 

 loss in weight amounted to 707 pounds, or 2.6 per cent. 



On the basis of the original weight, after deductmg the weight of 

 the samples dra^\m for analyses, the total shrinkage during the whole 

 storage period of 147 days, not including the loss during the three 

 elevations, was 1,522 pounds, or approximately 5.6 per cent. The 

 total shrmkage, includuig the shrinkage of 448 pounds during the 

 three elevations, was 1,970 pounds, or sUghtly more than 7 per cent. 

 On June 1, at the termination of the experiment, the average mois- 

 ture content of the corn w^as 14.7 per cent, or 4.1 per cent less than 

 the same corn contained at the beginning of the test on January 5. 

 During the same period there was likewise a marked change in the 

 quaUty of the corn, showing that there had been a partial decompo- 

 sition of the reserve food products during the course of the test 

 resulting m a shrinkage in weight far in excess of the reduction in 

 the percentage of moisture. The weight per bushel of the corn had 

 decreased from 54.7 pounds to 50 pounds; the sound corn from 97.1 

 to 1.1 per cent, and the kernels which were capable of germmation 

 from 89.6 to 1 per cent. 



EFFECT OF ATMOSPHERIC CONDITIONS ON THE SHRINKAGE OF 



CORN. 



It was found that the shruikage was not constant, but that during 

 certain periods there was a retardation in the rate of shrinkage or 

 even a temporary mcrease in weight due to the absorption of mois- 

 ture from the atmosphere. In this connection it must be borne in 

 mind that the hopper of the scale, being of wooden construction, 

 undoubtedly absorbed moisture from the atmosphere on damp and 

 rainy days the same as the corn. 



Figure 2 shows that whenever there was an increase in weight 

 or a retardation in the shrinkage the relative humidity of the atmos- 

 phere was very high between w^eighings, and in most cases a heavy 

 rainfall occurred just before such weighings were made. The reverse, 

 however, is not true in all cases; that is, all periods of high relative 

 humidity do not show in the diagram a corresponding increase in 

 weight, because the weighings were made only at irregular intervals 

 while the relative humidity records are daily. 



On January 21 there was an increase over the previous weigh- 

 mg, January 17, of 2.5 pounds. The relative humidity on Jan- 

 uary 17 was 81.5 per cent, and on January 21 it was 90.5 per 



[Cir. 81] 



