708 Report on Inspection Work of the 



in an attempt to derive some " standards " which would represent 

 the number of crop seeds in a given unit weight and thereby 

 materially shorten the method of making such tests. The results of 

 this study are reported in Bulletin No. 362 of this Station. During 

 the past year similar studies have been made with the official seed 

 samples, and in the main the findings agree with those obtained in 

 1912, namely: the number of seeds per unit weight in any one> kind 

 of seed was found to vary widely, depending upon the size of seed, 

 locality where grown, character of season in which the seed was 

 harvested* and (in the case of grass seeds) the grade of seed, and the 

 extent to which the hulls or chaff had been removed from the grains; 

 therefore, standards could not be applied with any degree of accuracy 

 to all samples collected during any one season, and in the case of 

 any sample the question might be raised as to the facts in regard 

 to that particular sample if the percentage of purity was determined 

 on the basis of an average number of seeds per unit weight for that 

 kind of crop seed. 



The demand for a short, practical method for finding the approxi- 

 mate percentage of foul and foreign seed in a sample seems to warrant 

 the publication of the standards derived from counts upon official 

 samples analyzed during the past two seasons. 



Table II gives the average number of seeds per unit weight for 

 the common crop seeds designated in the law as agricultural seeds. 

 These averages were obtained by counts made upon unit weights 

 of pure seed from samples obtained upon the open market by the seed 

 inspectors during the years 1912-1913. 



The operation of finding the approximate percentage of foreign 

 seed by count may be greatly shortened by considering the seeds 

 in a regulation weight test sample f as fractional parts, thereby giving 

 each kind of crop seed a definite value or " factor." The " factor " 

 designates the percentage which one seed would represent in the 



* As an illustration of the extent to which the number of crop seeds per unit weight 

 may vary from year to year, it was found by actual counts made upon redtop seed 

 samples collected in 1912 from seed grown in 1911 that the average number of seeds 

 per gram was 10,020, while in the case of the 1913 samples from seed grown in 1912 

 the average number of seeds per gram was 11,447, a difference of 1,427 seeds per 

 gram. In the case of Kentucky blue grass samples the average number of seeds per 

 gram for the corresponding years was 580 higher in the 1913 samples. 



t For the designated agricultural seeds the regulation weight test sample would 

 be for Canada and Kentucky blue grasses, and redtop grass seed 1 gram; alsike clover, 

 white clover, and timothy seed, 2 grams; alfalfa, red clover, and crimson clover seed, 

 5 grams; rape, 10 grams; and the vetches, 30 grams. 



