UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 516 



Joint Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief, and the Office of Marliets and 

 Rural Organization, CHARLES J. BRAND. Chief 



^'^^"^'U'A, 



Washington, D. C. 



December 28, 1916 



TABLE FOR CONVERTING WEIGHTS OF MECHAN- 

 ICAL SEPARATIONS INTO PERCENTAGES OF THE 

 SAMPLE ANALYZED.^ 



By E. G. BoERNER, Assistant in Grain Standardization. 

 INTRODUCTION. 



The rules and regulations for the enforcement of the United States 

 Grain Standards Act prescribe a definite procedure for securing a 

 representative sample upon which the grade of any particular lot or 

 parcel of shelled corn is to be based. 



The rules provide that the original sample must be not less than 

 2 quarts in quantity, of which approximately 1| pints must be placed 

 in an air-tight container and the remainder inclosed in a cloth sack. 

 The portion in the container is intended for the determination of the 

 percentage of moisture, and this portion should be used for that test 

 only. The remainder of the sample, contained in a cloth bag, will 

 approximate 2^ pints, and this portion is to be used for the remain- 

 ing determinations, including color, damaged corn (not including 

 heat damage), heat-damaged corn, and foreign material and cracked 

 corn. The grades specify the maximum and minimum percentages 

 permitted for the factors mentioned, and these percentages are to be 

 determined by weight. 



Because of the time involved, it is impracticable to make the 

 mechanical separations for color, damage, and foreign material and 

 cracked corn on the entire 2^ or more pints, and it therefore becomes 

 necessary, in most cases at least, to divide the sample in order to 

 obtain a smaller representative portion for the determination of the 

 factors mentioned. 



Experiments have shown that the sample upon which the deter- 

 minations for color, damage, foreign material, etc., are based should 



1 The work covered by this bulletin was done under the direction of Dr. J. W. T. Duvel, in charge of 

 the Office of Grain. Standardization of the Bureau of Plant Industry. Since August 18, 1916, the grain- 

 standardization work of the Department of Agriculture has been administered jointly by the Office of 

 Markets and Rural Organization and the Bureau of Plant Industry in connection with thp administration 

 of the United States Grain Standards Act. 

 71842°— Bull. 516—16 1 



