10 SHRINKAGE OF CORN IN STORAGE. 



cent. The average relative humidity during this period was 74.5 

 per cent. On March 2 there was an increase in weight of 12.5 

 pounds over the previous weighing, February 24. The average 

 relative humidity during this period was 81.4 per cent. On Feb- 

 ruary 28 and March 1 and 2 the relative humidity was 96, 97, and 

 99 per cent, respectively. On February 28 the precipitation 

 amounted to 0.71 of 1 inch, followed by 0.12 of 1 inch on March 1 

 and 0.03 of 1 inch on IMarcli 2. From this time on until March 22 

 the amount of precipitation was very small and the average relative 

 humidity was low. During this period the shrinkage was quite 

 rapid. On March 24 the relative humidity was 86 per cent, and 

 when the corn was weighed on March 25 there was an increase of 

 5 pounds over the previous weighing on March 22. The weighing 

 made on April 5 showed a gain in weight of 2.5 pounds as compared 

 with the weight on April 1. Here again the relative humidity was 

 high, being 87.5 per cent on April 4 and 81 per cent on April 5. 

 There was also 0.24 of 1 inch of rainfall during this period. After 

 April 5 the relative humidity was comparatively low until April 17, 

 when it reached 95 per cent, and on April 21 the relative humidity 

 was 90.5 per cent. At this time the corn showed signs of heating 

 and therefore the influence of the relative humidity and general 

 atmospheric conditions was lost in the increased amount of shrinkage 

 which accompanied the comparatively rapid deterioration of the 

 corn. 



SUMMARY. 



(1) The shrinkage test described in this circular was made with 

 500 bushels of shelled corn stored in the hopper of a scale in a grain 

 elevator, and extended over a period of 147 days, January 5 to June 

 1, 1910, during which time the corn was not "handled" except on 

 May 14. 



(2) At the beginning of the test the average moisture content 

 of the corn was 18.8 per cent. The average temperature of the corn 

 and the temperature of the air was 20° F. 



(3) The shrinkage in weight from January 5 to April 21, while 

 the corn remained in good condition, was approximately four- 

 tenths of 1 per cent. 



(4) The shrinkage in weight from April 21 to May 14 was approxi- 

 mately 2.6 per cent, during which time the corn went "out of con- 

 dition," becoming sour and hot, with a maximum temperature of 

 138° F. on May 2. 



(5) The shrinkage during the three elevations on May 14 was 

 448 pounds, or 1.65 per cent, on the basis of the actual weight of 

 corn in the hopper of the scale just previous to "handling." 



[Cir. 81] 



