18 THE COMMERCIAL GRADING OF CORN. 



the samples have been dried they should be weighed again with all 

 possible speed, as the meal readily absorbs moisture from the atmos- 

 phere upon being removed from the air-bath. It is best in all cases 

 to make duplicate moisture determinations, as errors are likely to be 

 made by even the most careful workman. These duplicates should be 

 made from separate grindings of different portions of the sample. 

 Where the results of the two determinations in the short-time drying 

 differ b} T more than about 1 per cent a third determination should be 

 made. 



COLOR. 



The percentage of color may be determined by simply counting out 

 the number of kernels of each color in a fair average sample. At 

 least 500 kernels should be used as a basis of reckoning. 



DAMAGED GRAINS. 



The percentage of damaged grains is determined by counting out 

 the number in a fair average sample of at least 500 grains and reckon- 

 ing the percentage of the number present. The damaged grain is 

 considered to include all cob-rotten, bin-burnt, moldy, or otherwise 

 unsound kernels. 



BROKEN GRAINS AND DIRT. 



This determination should be made on the basis of weights; that 



is, by weighing out a definite quantity of corn and separating b} 7 



means of the sieve mentioned above and by subsequent hand picking, 



all broken grains, meal, dirt, chaff, and foreign material of whatever 



nature. This determination should be made on a reasonably large 



sample of corn — at least a kilogram ('2.2 pounds). Where large 



scales are not at hand it is sometimes convenient to use the ordinary 



chondrometer or brass bucket employed in making the test weight per 



bushel of wheat, and the siftings and pickings may be weighed on the 



small balance used for the moisture work, and the percentage reckoned. 



The 5^-inch chondrometer holds about 1,800 grams (or 4 pounds) of 



corn. 



CLASSES AND GRADES OF CORN. 



The bulk of the corn crop of the United States is of the kind known 

 as dent corn. The grain trade recognizes three distinct classes of this 

 kind of corn, based on color. There are, of course, other colors of dent 

 corn, but practically all commercial corn may be classified into "} T el- 

 low corn/' ''white corn," and "mixed corn. 11 . There is not at present 

 any great degree of uniformit} T as to what shall constitute the color 

 limits of these classes, but the general opinion seems to be that the 

 following would be satisfactory: 



1. Yellow corn; at least 95 per cent yellow. 



2. White corn; at least 98 per cent white. 



3. Mixed corn; all corn not included above. 



