12 THE DETERIORATION OF -CORN IN STORAGE. 



from April 27 to May 25 and from May 25 to Jime 3, together with the 

 daily maximum air temperature and the weather record for the same 

 period. The diagram also shows that only the corn near the surface 

 was influenced by the temperature of the outside air. 



LOSS IN MOISTURE AND SHRINKAGE. 



When the undried corn from the bin was first loaded into car No. 

 75197, on April 27, the average moisture content was 17.47 per cent. 

 On May 25, when the maximum temperature of the corn was 122° F., 

 the average moisture content of the surface corn was 13.55 per cent. 

 Samples taken from 5 inches below the surface showed a moisture 

 content of 17 per cent. The highest moisture content found was 

 17.5 per cent, in samples taken at the point where the temperature 

 was 122° F. 

 • The shrinkage in weight in the layer of corn at the surface, based on 

 the reduction in moisture of 3.92 per cent, was 4.53 per cent. On 

 May 25 this corn was unloaded and re weighed by the weighman of 

 the Chamber of Commerce on the scales regularly used at the ele- 

 vator. The loss in weight in the loading and unloading and through 

 evaporation while in the car from April 27 to May 25 was 367 pounds, 

 or 0.728 of 1 per cent. This corn was then handled over five elevators, 

 screened, weighed, and reloaded. In this handling and reloading 

 the moisture content was reduced to 16.55 per cent, or 0.92 of 1 per 

 cent less than when the corn was first loaded into the car on April 

 27, which is equivalent to a loss in weight of 1.1 per cent due to the 

 evaporation of moisture while in the car and in the handling of the 

 hot corn in the elevator. On June 3, this car of corn, cooled by 

 handhng, was again hot, the temperature having increased from 73° F. 

 to 112° F. from May 25 to June 3. The average moisture content of 

 the surface corn was only 13.95 per cent, as compared with 16.55 per 

 cent when reloaded, a reduction in moisture of 2.6 percent in 9 days. 

 The low moisture content of the surface corn showed that water 

 was being lost by evaporation and that this evaporation is quite 

 rapid when the temperature of the corn is relatively high. It must 

 be remembered, however, that this car was opened frequently and 

 the corn on the surface more or less disturbed in the securing of sam- 

 ples, in reading temperatures, etc., so that the same results might 

 not apply in the same degree to corn in transit where the cars are 

 unopened from point of shipment to destinati(m. 



Approved : 



James Wilson, 



Secretary of Agriculture. 



Washington, D. C, Novemherd, 1909. 

 IClr. 4:i] 



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