New York Agricultural Experiment Station. 709 



Table II. — Average Number of Seeds per Unit Weight. 



Kind of crop seed. 



Alfalfa 



Alsike clover 



Canada blue grass . . 



Crimson clover 



Kentucky blue grass 



Orchard grass 



Rape, Dwarf Essex . 



Red clover 



Redtop 



Timothy 



1 Vetch, spring 



2 Vetch, winter 



White clover 



Number of 



seeds per 



gram. 



Av. 



506 



1,525 



5,965 



323 



5,297 



1,420 



230 



655 



10,733 



2,794 



21 



37 



1,579 



Number of 

 seeds in 



regulation 

 sample. 



Av. 

 2,529 

 3,051 

 5,965 

 1,616 

 5,297 

 2,840 

 2,303 

 3,277 

 10,733 

 5,588 

 638 

 1,112 

 3,159 



Number of 



seeds per 



pound. 



Av. 



229,431 



691,967 



2,705,724 



146,603 



2,402,720 



644,112 



104,464 



297,244 



4,868,488 



1,267,358 



9,616 



16,783 



716,461 



Factor. 3 



0.040 

 0.032 

 0.017 

 0.061 

 0.019 

 0.035 

 0.043 

 0.030 

 0.010 

 0.018 

 156 

 0.090 

 0.031 







1 Spring, or common vetch, Vicia sativa. 



2 Winter, sand, or hairy, vetch, Vicia villosa. 



3 See last paragraph on page 131 for explanation of the " Factor." 



regulation weight of sample taken for that particular kind of crop 

 seed, and is derived from the preceding table. After having weighed 

 out the test sample it is spread out upon a smooth, white surface 

 and the foul or foreign seeds counted. The number of such foul or 

 foreign seeds found in the sample is then multiplied by the " factor " 

 for the kind of crop seed in which the seed impurities were found, 

 the result being the approximate percentage of such foul or foreign 

 seed in the sample. The application of this method is based upon 

 the assumption that every foreign seed present in the test sample 

 usurps the place of a crop seed, and it should be understood that 

 the method is intended to be applied only when dealing with the 

 above designated agricultural seeds which have been recleaned and 

 are at least of average grade. With such seeds there is no great 

 sacrifice of accuracy with the method. This method is of greatest 

 value when the analyst has made a mechanical separation of the 

 seed sample for the purpose of determining percentage of purity 

 by weight, since the foul or foreign seeds in the test sample are 

 then easily counted and the number multiplied by the "factor" 

 for the kind of crop seed in which they were found. The " factors " 

 cannot be used with crop seed mixtures. 



