New York Agricultural Experiment Statiox. 707 



A sample of redtop seed (No. 976F), contaminated with timothy- 

 seed, because of the larger size and weight of the timothy, showed 

 8.0 per ct. foreign seed by weight but only 4.56 per ct. by count. 



Red clover seed sample No. 22, which was badly infested with 

 many small weed seeds, notably those of Rugel's plantain, lamb's 

 quarters, mayweed and small-seeded dodder, showed 4.0 per ct. of 

 such seeds by weight or 8.75 per ct. by count. 



Timothy seed sample No. 1039 contained rough cinquefoil, blue 

 grass, and sheep sorrel seeds to the extent of 4.7 per ct. by weight, 

 or 12.6 per ct. by count. Another sample of timothy seed contained 

 redtop grass seed, rough cinquefoil and other small weed seeds to 

 the extent of 7.5 per ct. by weight or 17.1 per ct. by count. Timothy 

 seed sample No. 1040F contained mouse-ear chick weed, blue grass 

 and other small seeds to the extent of 1.0 per ct. by weight, but when 

 the " count " method was applied the percentage of such seeds was 

 found to be 5.9, which would constitute a violation of the seed law. 



It seems evident, then, that the smaller and lighter the seed impuri- 

 ties are with respect to the size and weight of the crop seed in which 

 they are found, the greater the variation in the two methods, the 

 percentage of impurity by count increasing more rapidly than the 

 percentage by weight as the relative size of the impurities decreases. 



The foregoing facts may account for some of the apparent dis- 

 crepancies in percentages of impurity of some samples collected 

 in this State, since some dealers have based their guarantees of purity 

 upon percentages as determined by weight and not by count as is 

 required by the provisions of the seed law. 



There are certain instances in which it appears as if it would be a 

 practical impossibility for seedsmen to determine the exact purity 

 percentage by count of some kinds of seed; as is illustrated in the 

 above cited case of the redtop grass seed sample containing seeds of 

 a species of rush. In this sample it was necessary to dissolve the 

 mucilaginous substance surrounding the bunches of seeds with an 

 alcoholic preparation and later count them under a low-power 

 binocular microscope. 



SHORT METHOD FOR THE COUNT DETERMINATION OF PERCENTAGE 



OF FOREIGN SEED. 



Following the enactment, July 1, 1912, of the present seed law the 

 writer made a study of the "count" method of purity determination 



