SEED ANALYSIS 75 
different parts of the bag or container, usually from the top, 
middle, and bottom. From the sample from 2 to 5 grams are 
weighed out, and the impurities and desirable seeds are then sepa- 
rated, usually by means of a lens like the one in Figure 72. By 
6Wild oe 
. 7 29, 
@ x8 
N 
10 Hexen MRuckhorn 12 Byacteds a 
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at a \d 
BRagweed 6 Tinstle 12 Nae 
Fic. 73. — Some weed seeds and fruits commonly found among Red Clover 
seeds. Enlarged and about natural size. From Farmers’ Bulletin 455, 
U.S. Dept. of Agriculture. 
dividing the weight of the desirable seeds and the weight of the 
impurities by the number of grams analyzed, the percentage of 
each is obtained. Thus, if 5 grams are analyzed and the weight 
of the desirable seeds found is 4.8 grams, then = = 96 per cent, 
which is the percentage of purity. In determining the kinds of 
