CHAPTER XVII. 



SAMPLING, WEIGHING AND TESTING GATHERED CREAM. 

 CREAM SAMPLING AND SAMPLERS. 



Taking an Aliquot Sample. This means that the 

 amount of cream taken for the composite test jar, must 

 always be proportional to the amount of cream furnished. 

 If cream always had the same richness, or if always the 

 same amount were furnished, the dipper method of 

 sampHng would give satisfactory results, provided the 

 cream was thoroughly mixed before sampling. But since 

 we rarely find two batches of cream alike, either in quan- 

 tity or quality, the necessity of taking an aliquot sample 

 becomes apparent. This may be made perfectly plain by 

 the following illustration : 



Feb. I patron X furnishes 50 lbs. of 20% cream. 

 Feb. 2 patron X furnishes 30 lbs. of 30% cream. 

 Feb. 3 patron X furnishes 20 lbs. of 40% cream. 



Dividing the total butterfat furnished during the three 

 days by the total pounds of cream we get 2j, which repre- 

 sents the correct average test. This test would be secured 

 by taking aliquot samples. The test by the dipper method 

 would equal the sum of the three tests divided by three. 

 Thus 2o+30+40-f-3^30, the average test by the dipper 

 method, differing from the correct average test by 3%. 

 By the dipper method the same amount of cream is taken 

 for a sample, regardless of the amount of cream fur- 

 nished. 



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