

GRADES FOR COMMERCIAL CORN. 6 



SECURING A REPRESENTATIVE SAMPLE FROM THE BULK. 



In the grading of commercial corn no factor is of greater importance 

 than the securing of a sample representative of the bulk. Likewise, 

 no factor is more frequently neglected. In the application of these 

 grades to car-lot shipments of corn it is recommended that not less 

 than five probes with a suitable grain trier be taken in such a way 

 that the composite sample thus secured will represent the average 

 of the car as nearly as practicable. On cars not uniformly loaded, 

 such additional probes should be made as, in the opinion of the 

 sampler, may be necessary to secure a representative sample. In 

 cars that show distinct evidence of having been "plugged," and in 

 all cases of marked variation in the quality or condition of the corn 

 in different parts of the lot being examined, a separate composite 

 sample should be taken to represent each such portion. 



If only a part of the grain secured by the various probes is taken 

 to a central office for more careful examination and final grading, 

 the mixing of the individual sample at the car should receive most 

 careful consideration. Very satisfactory results can be secured by 

 emptying the contents of the trier each time on a piece of canvas 

 and, after all probes have been made, thoroughly mixing the samples 

 on the canvas, finally rolling the sample on the canvas, somewhat as 

 an expert would roll a cigarette, except that the canvas should be 

 held by two opposite sides, which two sides should be securely fas- 

 tened to a stick or rod. The larger composite sample can then be 

 readily divided into two approximately equal parts by seizing the 

 fold of the canvas from beneath with the thumb and index finger; 

 then, emptying one portion into the car, the other is retained for the 

 office sample. 



Representative samples can not be secured by emptying the con- 

 tents of the trier, after each probe, on top of the grain, then roughly 

 mixing and taking a portion thereof, usually including a part of the 

 surface corn, as a composite sample for the basis of grading. Such 

 samples not only fail to represent the bulk, but are misleading, 

 especially from the standpoint of dirt and cracked corn. Likewise, 

 composite samples made up by emptying only a part of the contents 

 of the trier into the can or sample bag can not, as a rule, be consid- 

 ered representative. 



In the sampling of large lots of grain, such as occur in the loading 

 of steamers, at least one representative sample made up of a series 

 of samples from the various drafts should be taken for each 5,000 

 bushels. 



In the sampling of ear corn, where the moisture content is the 

 important factor, at least 20 representative ears should be taken at 

 random for each 1,000 bushels. In wagon lots of 100 bushels or 



