EXPERIMENT STATION BULLETINS. 



177 



fuls of seed should be placed in a pile on one side of the paper, which should be 

 laid on a table near a window. Then, holding the lens in one hand, with the 

 knife blade draw small quantities of the seed frqm the edge of the pile, spread 

 them out so that each one can be readily seen and examine them carefully through 

 the lens. Remove all foreign material, including the weed speeds to one corner 

 of the paper while the remaining clean seeds are pushed to one side. Continue 

 this process until all of the sample has been thoroughly sorted. Two piles have 

 now been formed, one consisting of clean seed, the other of impurities containing 

 the weed seeds. 



If a delicate balance were at hand it would now be possible to determine the 

 per cent of impurities by weighing both piles and dividing the weight of the im- 

 purities by the weight of the sample before sorting. However, it is possible to 



Fig. 1. 



-Examining clover seed for impurities and weed seeds. 



to tlie lens. 



Place the eye close down 



gain some idea sufficient for a rough estimate by comparing the size of the two 

 amounts. The weed seeds may be carefully saved in a small dish or vial for 

 further examination and a sample of the clean seed counted out for a germination 

 test. 



THE GERMIXATIOX TEST. 



The value of this test will depend to a considerable extent upon the care with 

 which it is performed. The necessary articles are a soup or dinner plate, with a 

 somewhat smaller plate or a pane of glass for covering it, and some pieces of 

 rather thick, clean cloth. For one or two samples of small seeds a tea saucer 

 covered with a piece of window glass will be found ample, while the cloth, when 

 folded, may be about three by- four inches in size. 



The seed for testing is first to be thoroughly mixed and one hundred seeds 

 counted out, taking them just as they come, regardless of size or plumpness, the 

 idea being to get as nearly as possible an average sample. A piece of the cloth 



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