SELECTION AXD SAMPLING OF SEED. 163 



importance is attached to color. On the other hand, 

 the odor of seed is a reliable basis and certain depend- 

 ence may be placed on it; it should be very much like 

 hay. Again, when the smell is rather mouldy, it would 

 indicate that the seed had been kept in a damp place or 

 had not been properly handled after harvesting; the 

 odor from the decomposition of the organic portion of 

 the plant is very offensive. Old seeds have a charac- 

 teristic smell, which permit one, with a little experience, 

 to recognize them at once. Those who make a prac- 

 tice of mixing these seed with their new crop take the 

 precaution of disguising the smell by the use of anise- 

 seed oil, or a weak solution of permanganate of potash. 

 Impurities. 



Five to ten grams of the seed are carefully 

 weighed and then spread upon a sheet of paper. 

 Each seed is pushed to one side and counted. 

 The weight of the seed used, N grams, and the weight 

 of the clean seed, n grams, are substituted in the fol- 

 lowing formula in calculating the percentage of 

 impurities, I :I^(N — n -^ N) loo. This estimation 

 of impurities at first seems very simple, but in reality 

 it offers many difficulties, as the results obtained fre- 

 quently do not agree. The shaking of the bottle con- 

 taining the sample demands certain precautions; if 

 alwavs in one direction, the deposit will be found in 

 one spot, while if shaken with cork down, to one side, 

 etc., the impurities are evenly spread through the entire 

 mass of seed. An important question is, Whether the 

 leaves and adhering stems should be separated and 

 counted as impurities or left on and not considered? 

 Many discussions occur relating to this custom, and in 

 one case the impurities may be found to be four per 

 cent, and in the other only two per cent. However, 

 when that question is settled, it is well to repeat the 

 operation of impurity estimation at least three times 

 and to take an average. 



A given weight of the seed is well shaken in a 



